diff --git a/src/css/properties/transition.rs b/src/css/properties/transition.rs
index 48ff249cd9d7..dfbf06f6c5c7 100644
--- a/src/css/properties/transition.rs
+++ b/src/css/properties/transition.rs
@@ -365,9 +365,10 @@ mod transition_handler_body {
             let mut _timing_functions: Option<(SmallList<EasingFunction, 1>, VendorPrefix)> =
                 self.timing_functions.take();
 
+            let mut sources: Option<Vec<u32>> = None;
             let mut rtl_properties: Option<SmallList<PropertyId, 1>> =
                 if let Some(p) = &mut _properties {
-                    expand_properties(&mut p.0, arena, context)
+                    expand_properties(&mut p.0, &mut sources, arena, context)
                 } else {
                     None
                 };
@@ -389,13 +390,20 @@ mod transition_handler_body {
                 let intersection =
                     *property_prefixes & *duration_prefixes & *delay_prefixes & *timing_prefixes;
                 if !intersection.is_empty() {
-                    let transitions =
-                        get_transitions(arena, properties, durations, delays, timing_functions);
+                    let transitions = get_transitions(
+                        arena,
+                        properties,
+                        sources.as_deref(),
+                        durations,
+                        delays,
+                        timing_functions,
+                    );
 
                     if let Some(rtl_properties2) = &mut rtl_properties {
                         let rtl_transitions = get_transitions(
                             arena,
                             rtl_properties2,
+                            sources.as_deref(),
                             durations,
                             delays,
                             timing_functions,
@@ -468,40 +476,35 @@ mod transition_handler_body {
     fn get_transitions(
         arena: &bun_alloc::Arena,
         properties: &mut SmallList<PropertyId, 1>,
+        sources: Option<&[u32]>,
         durations: &mut SmallList<Time, 1>,
         delays: &mut SmallList<Time, 1>,
         timing_functions: &mut SmallList<EasingFunction, 1>,
     ) -> SmallList<Transition, 1> {
-        #[inline]
-        fn cycle_bump(idx: &mut u32, len: u32) {
-            *idx = (*idx + 1) % len;
-        }
-
         // transition-property determines the number of transitions. The values of other
         // properties are repeated to match this length.
         let mut transitions = SmallList::<Transition, 1>::init_capacity(1);
-        let mut durations_idx: u32 = 0;
-        let mut delays_idx: u32 = 0;
-        let mut timing_idx: u32 = 0;
-        for property_id in properties.slice() {
-            let duration = if durations.len() > durations_idx {
-                durations.at(durations_idx).deep_clone(arena)
+        debug_assert!(sources.is_none_or(|sources| sources.len() == properties.slice().len()));
+        for (index, property_id) in (0u32..).zip(properties.slice()) {
+            // Each name takes the values of its entry as written. lightningcss matches by position, which shifts them.
+            let source = sources.map_or(index, |sources| sources[index as usize]);
+            let duration = if !durations.is_empty() {
+                durations.at(source % durations.len()).deep_clone(arena)
             } else {
                 Time::Seconds(0.0)
             };
-            let delay = if delays.len() > delays_idx {
-                delays.at(delays_idx).deep_clone(arena)
+            let delay = if !delays.is_empty() {
+                delays.at(source % delays.len()).deep_clone(arena)
             } else {
                 Time::Seconds(0.0)
             };
-            let timing_function = if timing_functions.len() > timing_idx {
-                timing_functions.at(timing_idx).deep_clone(arena)
+            let timing_function = if !timing_functions.is_empty() {
+                timing_functions
+                    .at(source % timing_functions.len())
+                    .deep_clone(arena)
             } else {
                 EasingFunction::Ease
             };
-            cycle_bump(&mut durations_idx, durations.len());
-            cycle_bump(&mut delays_idx, delays.len());
-            cycle_bump(&mut timing_idx, timing_functions.len());
             let transition = Transition {
                 property: property_id.deep_clone(arena),
                 duration,
@@ -525,6 +528,7 @@ mod transition_handler_body {
 
     fn expand_properties(
         properties: &mut SmallList<PropertyId, 1>,
+        sources: &mut Option<Vec<u32>>,
         arena: &bun_alloc::Arena,
         context: &mut PropertyHandlerContext,
     ) -> Option<SmallList<PropertyId, 1>> {
@@ -541,11 +545,24 @@ mod transition_handler_body {
             }
         }
 
+        // Once an entry becomes several names, each name keeps the index of its entry as written.
+        #[cold]
+        fn record_names(sources: &mut Option<Vec<u32>>, source: u32, names: u32, capacity: u32) {
+            let sources = sources.get_or_insert_with(|| {
+                let mut sources = Vec::with_capacity(capacity as usize);
+                sources.extend(0..source);
+                sources
+            });
+            sources.resize(sources.len() + names as usize, source);
+        }
+
         let mut rtl_properties: Option<SmallList<PropertyId, 1>> = None;
         let mut i: u32 = 0;
+        let mut source: u32 = 0;
 
         // Expand logical properties in place.
         while i < properties.len() {
+            let start = i;
             let result = get_logical_properties(properties.at(i));
             match result {
                 LogicalPropertyId::Block(feature, block)
@@ -555,7 +572,7 @@ mod transition_handler_body {
                     if let Some(rtl) = &mut rtl_properties {
                         replace(arena, rtl, block, i);
                     }
-                    i += 1;
+                    i += u32::try_from(block.len()).expect("int cast");
                 }
                 LogicalPropertyId::Inline(feature, ltr, rtl)
                     if context.should_compile_logical(feature) =>
@@ -611,6 +628,12 @@ mod transition_handler_body {
                     i += 1;
                 }
             }
+
+            let names = i - start;
+            if names > 1 || sources.is_some() {
+                record_names(sources, source, names, properties.len());
+            }
+            source += 1;
         }
 
         rtl_properties
diff --git a/test/bundler/css/mask-geometry-box.test.ts b/test/bundler/css/mask-geometry-box.test.ts
index ea5d70a8fca7..14ae96d28bda 100644
--- a/test/bundler/css/mask-geometry-box.test.ts
+++ b/test/bundler/css/mask-geometry-box.test.ts
@@ -41,4 +41,29 @@ describe("css", () => {
       expect(output).toContain("padding-box");
     },
   });
+
+  // The default browser targets add `-webkit-mask-box-image` in front of `mask-border`. Both keep the 2s.
+  for (const backend of ["cli", "api"] as const) {
+    itBundled(`css/transition-mask-border-keeps-its-duration-${backend}`, {
+      backend,
+      files: {
+        "index.css": /* css */ `
+          .a {
+            transition: mask-border 2s, opacity 3s;
+          }
+        `,
+      },
+      outdir: "/out",
+      entryPoints: ["/index.css"],
+      onAfterBundle(api) {
+        api.expectFile("/out/index.css").toMatchInlineSnapshot(`
+          "/* index.css */
+          .a {
+            transition: -webkit-mask-box-image 2s, mask-border 2s, opacity 3s;
+          }
+          "
+        `);
+      },
+    });
+  }
 });
diff --git a/test/js/bun/css/css.test.ts b/test/js/bun/css/css.test.ts
index 890ffa4dcd95..b2c18ed62520 100644
--- a/test/js/bun/css/css.test.ts
+++ b/test/js/bun/css/css.test.ts
@@ -7159,6 +7159,153 @@ describe("css tests", () => {
         chrome: Some(95 << 16),
       },
     );
+
+    // One entry of a `transition` can become several names: a logical shorthand becomes its physical longhands,
+    // and `mask-border` gets `-webkit-mask-box-image`. Each name keeps the values of the entry it came from.
+    describe("an entry that becomes several names keeps its duration, delay and timing function", () => {
+      const safari = (version: number) => ({ safari: Some(version << 16) });
+      const rtlLangs = "ae ar arc bcc bqi ckb dv fa glk he ku mzn nqo pnb ps sd ug ur yi"
+        .split(" ")
+        .map(lang => `:lang(${lang})`)
+        .join(", ");
+      // The rules that one rule with an inline logical property becomes for Safari 8.
+      const directionRules = (ltr: string, rtl: string) => `
+        .foo:not(:-webkit-any(${rtlLangs})) { ${ltr} }
+        .foo:not(:is(${rtlLangs})) { ${ltr} }
+        .foo:-webkit-any(${rtlLangs}) { ${rtl} }
+        .foo:is(${rtlLangs}) { ${rtl} }
+      `;
+
+      prefix_test(
+        `.foo { transition: mask-border 1s, opacity 2s }`,
+        `.foo { transition: -webkit-mask-box-image 1s, mask-border 1s, opacity 2s; }`,
+        safari(15),
+      );
+      prefix_test(
+        `.foo { transition: inset 1s, opacity 2s }`,
+        `.foo { transition: top 1s, bottom 1s, left 1s, right 1s, opacity 2s; }`,
+        safari(8),
+      );
+      prefix_test(
+        `.foo { transition: margin-block 1s, opacity 2s, color 3s }`,
+        `.foo { transition: margin-top 1s, margin-bottom 1s, opacity 2s, color 3s; }`,
+        safari(8),
+      );
+      prefix_test(
+        `.foo { transition: border-block-color 1s, border-inline-width 2s, opacity 3s }`,
+        `.foo { transition: border-top-color 1s, border-bottom-color 1s, border-left-width 2s, border-right-width 2s, opacity 3s; }`,
+        safari(8),
+      );
+      prefix_test(
+        `.foo { transition: mask-composite 1s, mask-mode 2s, opacity 3s }`,
+        `.foo { transition: -webkit-mask-composite 1s, mask-composite 1s, -webkit-mask-source-type 2s, mask-mode 2s, opacity 3s; }`,
+        safari(15),
+      );
+      prefix_test(
+        `.foo { transition: inset 1s linear 3s, opacity 2s ease-in 4s }`,
+        `.foo { transition: top 1s linear 3s, bottom 1s linear 3s, left 1s linear 3s, right 1s linear 3s, opacity 2s ease-in 4s; }`,
+        safari(8),
+      );
+      // A shorter list repeats over the entries as written, and a value past the last entry is not used.
+      prefix_test(
+        `.foo { transition: inset 1s, opacity 2s, color 3s; transition-duration: 4s, 5s }`,
+        `.foo { transition: top 4s, bottom 4s, left 4s, right 4s, opacity 5s, color 4s; }`,
+        safari(8),
+      );
+      prefix_test(
+        `.foo { transition: inset 1s; transition-duration: 4s, 5s }`,
+        `.foo { transition: top 4s, bottom 4s, left 4s, right 4s; }`,
+        safari(8),
+      );
+      // daisyUI ships this shape in its megamenu, with `linear()` as the first easing.
+      prefix_test(
+        `.foo { transition: inset .3s cubic-bezier(.2, .9, .3, 1.1), background-color .2s ease-out }`,
+        `.foo {
+          transition: top .3s cubic-bezier(.2, .9, .3, 1.1), bottom .3s cubic-bezier(.2, .9, .3, 1.1), left .3s cubic-bezier(.2, .9, .3, 1.1), right .3s cubic-bezier(.2, .9, .3, 1.1), background-color .2s ease-out;
+        }`,
+        safari(14),
+      );
+      // The order as written stays, so the last entry for a property still decides.
+      prefix_test(
+        `.foo { transition: top 5s, inset 1s, left 7s }`,
+        `.foo { transition: top 5s, top 1s, bottom 1s, left 1s, right 1s, left 7s; }`,
+        safari(8),
+      );
+      prefix_test(
+        `.foo { transition: all 1s, inset 2s }`,
+        `.foo { transition: all 1s, top 2s, bottom 2s, left 2s, right 2s; }`,
+        safari(8),
+      );
+      prefix_test(
+        `.foo { transition: inset 1s, opacity 2s; transition-duration: 3s, 4s }`,
+        `.foo { transition: top 3s, bottom 3s, left 3s, right 3s, opacity 4s; }`,
+        safari(8),
+      );
+      prefix_test(
+        `.foo { transition-duration: 3s, 4s; transition: inset 1s, opacity 2s }`,
+        `.foo { transition: top 1s, bottom 1s, left 1s, right 1s, opacity 2s; }`,
+        safari(8),
+      );
+      // The handler writes what it holds when a prefixed value differs or a longhand is not parsed.
+      prefix_test(
+        `.foo { -webkit-transition: inset 1s, opacity 2s; transition: inset 3s, opacity 4s }`,
+        `.foo {
+          -webkit-transition: top 1s, bottom 1s, left 1s, right 1s, opacity 2s;
+          transition: top 3s, bottom 3s, left 3s, right 3s, opacity 4s;
+        }`,
+        safari(8),
+      );
+      prefix_test(
+        `.foo { transition: inset 1s, opacity 2s; transition-timing-function: var(--ease) }`,
+        `.foo {
+          transition: top 1s, bottom 1s, left 1s, right 1s, opacity 2s;
+          transition-timing-function: var(--ease);
+        }`,
+        safari(8),
+      );
+      prefix_test(
+        `.foo { transition: inset 1s, opacity 2s, transform 3s }`,
+        `.foo {
+          -webkit-transition: top 1s, bottom 1s, left 1s, right 1s, opacity 2s, -webkit-transform 3s, transform 3s;
+          transition: top 1s, bottom 1s, left 1s, right 1s, opacity 2s, -webkit-transform 3s, transform 3s;
+        }`,
+        safari(6),
+      );
+      // Both direction rules, with the inline logical property in front of the entry and behind it.
+      prefix_test(
+        `.foo { transition: margin-inline-start 1s, inset 2s, opacity 3s }`,
+        directionRules(
+          `transition: margin-left 1s, top 2s, bottom 2s, left 2s, right 2s, opacity 3s;`,
+          `transition: margin-right 1s, top 2s, bottom 2s, left 2s, right 2s, opacity 3s;`,
+        ),
+        safari(8),
+      );
+      prefix_test(
+        `.foo { transition: inset 1s, margin-inline-start 2s, opacity 3s }`,
+        directionRules(
+          `transition: top 1s, bottom 1s, left 1s, right 1s, margin-left 2s, opacity 3s;`,
+          `transition: top 1s, bottom 1s, left 1s, right 1s, margin-right 2s, opacity 3s;`,
+        ),
+        safari(8),
+      );
+      // Prints `color 1s, opacity 1s`: the later property list meets one duration per name of the first list.
+      cssTestTodo(
+        `.foo { transition: inset 1s, opacity 2s } .foo { transition-property: color, opacity }`,
+        `.foo { transition: color 1s, opacity 2s; }`,
+        safari(8),
+      );
+
+      // Nothing becomes several names without targets, or for targets that need nothing.
+      minify_test(
+        ".foo { transition: inset 1s, mask-border 2s, transform 3s }",
+        ".foo{transition:inset 1s,mask-border 2s,transform 3s}",
+      );
+      prefix_test(
+        `.foo { transition: inset 1s, mask-border 2s, transform 3s, opacity 4s }`,
+        `.foo { transition: inset 1s, mask-border 2s, transform 3s, opacity 4s; }`,
+        { chrome: Some(130 << 16) },
+      );
+    });
   });
 
   describe("animation", () => {