diff --git a/patches/glimmer-scoped-css@0.8.1.patch b/patches/glimmer-scoped-css@0.8.1.patch
new file mode 100644
index 00000000000..230e5bda8f5
--- /dev/null
+++ b/patches/glimmer-scoped-css@0.8.1.patch
@@ -0,0 +1,47 @@
+diff --git a/dist/ast-transform-8c8ef165.js b/dist/ast-transform-8c8ef165.js
+index 066d5bc5f9e350d855d7d48ae56f47b4e33907bc..3483e529a009cbe4b6019ada0c332411b660595a 100644
+--- a/dist/ast-transform-8c8ef165.js
++++ b/dist/ast-transform-8c8ef165.js
+@@ -164,8 +164,41 @@ function decodeCSS(encodedCSSString) {
+   return new TextDecoder().decode(Uint8Array.from(binString, m => m.codePointAt(0)));
+ }
+ 
++// The scope prefix must be the same for the same source on every machine:
++// prerendered HTML carries the prefixes of the build that rendered it, and a
++// build at another path must still style it. A file on disk is identified by
++// its path relative to the working directory of the build. Anything else keeps
++// its filename, including the synthetic paths a realm transpiles under
++// (`/spec.gts`), which do not exist on disk and are already stable. Both
++// paths are resolved through symlinks first: `process.cwd()` is always
++// resolved, and a filename reached through a symlink would otherwise give a
++// path up to the root and back down, which holds the absolute path again.
++function cwdRelativeId(filename) {
++  let fs;
++  try {
++    fs = require('fs');
++  } catch {
++    return undefined;
++  }
++  if (
++    !fs ||
++    typeof fs.existsSync !== 'function' ||
++    typeof fs.realpathSync !== 'function' ||
++    typeof process === 'undefined' ||
++    typeof process.cwd !== 'function' ||
++    typeof filename !== 'string' ||
++    !path.isAbsolute(filename) ||
++    !fs.existsSync(filename)
++  ) {
++    return undefined;
++  }
++  return path
++    .relative(fs.realpathSync(process.cwd()), fs.realpathSync(filename))
++    .split(path.sep)
++    .join('/');
++}
+ function uniqueIdentifier(filename) {
+-  return superFastMd5.md5(filename).slice(0, 10);
++  return superFastMd5.md5(cwdRelativeId(filename) ?? filename).slice(0, 10);
+ }
+ function generateScopedCSSPlugin(options) {
+   return env => {
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index bcf5425b790..ba895997329 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -742,6 +742,7 @@ patchedDependencies:
   ember-css-url@1.0.0: 0e5253a008cc7bf02424d786e7a8fb2397bc48962f3cd1443f2c0fdd8200c96d
   ember-eslint-parser: 364c7e71472801c87618bf2b2cdabd256358166bbe107f29d321ab35d0a53425
   ember-source: ea945024993105fb6cc4ae5cb5e9ea8e0eff6cd5fe0b0033c43dd0cf9453eb0d
+  glimmer-scoped-css@0.8.1: 986cd65c9ffc8b062a227f0d09dd76f021b1654c7d90185548f5647e9eca632b
   magic-string@0.25.9: 32dda55b40f0bc860d0a8e93bee54d8005c34ed7ac5faed23ce9f5e5f57eea39
   matrix-js-sdk@38.3.0: 9916a9e914367042bf4e45522e7ccc4cfafb8893276852608baa57080b654f89
   monaco-editor@0.52.2: bdefe071221b87c7c15e1add6739d24d486f543dbad0d714ae586085204626cd
@@ -1701,7 +1702,7 @@ importers:
         version: 3.3.0(@typescript-eslint/parser@8.67.0(eslint@9.39.5(supports-color@8.1.1))(supports-color@8.1.1)(typescript@5.9.3))(eslint@9.39.5(supports-color@8.1.1))(supports-color@8.1.1)(typescript@5.9.3)
       glimmer-scoped-css:
         specifier: 'catalog:'
-        version: 0.8.1(supports-color@8.1.1)
+        version: 0.8.1(patch_hash=986cd65c9ffc8b062a227f0d09dd76f021b1654c7d90185548f5647e9eca632b)(supports-color@8.1.1)
       globals:
         specifier: ^15.14.0
         version: 15.15.0
@@ -1942,7 +1943,7 @@ importers:
         version: 8.2.6(eslint@8.57.1(supports-color@8.1.1))
       glimmer-scoped-css:
         specifier: 'catalog:'
-        version: 0.8.1(supports-color@8.1.1)
+        version: 0.8.1(patch_hash=986cd65c9ffc8b062a227f0d09dd76f021b1654c7d90185548f5647e9eca632b)(supports-color@8.1.1)
       prettier:
         specifier: 'catalog:'
         version: 3.8.4
@@ -3260,7 +3261,7 @@ importers:
         version: link:../glimmer-motion
       glimmer-scoped-css:
         specifier: 'catalog:'
-        version: 0.8.1(supports-color@8.1.1)
+        version: 0.8.1(patch_hash=986cd65c9ffc8b062a227f0d09dd76f021b1654c7d90185548f5647e9eca632b)(supports-color@8.1.1)
       ignore:
         specifier: 'catalog:'
         version: 5.3.2
@@ -3763,7 +3764,7 @@ importers:
         version: 11.3.5
       glimmer-scoped-css:
         specifier: 'catalog:'
-        version: 0.8.1(supports-color@8.1.1)
+        version: 0.8.1(patch_hash=986cd65c9ffc8b062a227f0d09dd76f021b1654c7d90185548f5647e9eca632b)(supports-color@8.1.1)
       glob:
         specifier: 'catalog:'
         version: 11.1.0
@@ -4048,7 +4049,7 @@ importers:
         version: 5.0.2
       glimmer-scoped-css:
         specifier: 'catalog:'
-        version: 0.8.1(supports-color@8.1.1)
+        version: 0.8.1(patch_hash=986cd65c9ffc8b062a227f0d09dd76f021b1654c7d90185548f5647e9eca632b)(supports-color@8.1.1)
       http-status-codes:
         specifier: 'catalog:'
         version: 2.3.0
@@ -27170,7 +27171,7 @@ snapshots:
 
   github-slugger@2.0.0: {}
 
-  glimmer-scoped-css@0.8.1(supports-color@8.1.1):
+  glimmer-scoped-css@0.8.1(patch_hash=986cd65c9ffc8b062a227f0d09dd76f021b1654c7d90185548f5647e9eca632b)(supports-color@8.1.1):
     dependencies:
       '@embroider/addon-shim': 1.10.3(supports-color@8.1.1)
       js-string-escape: 1.0.1
diff --git a/pnpm-workspace.yaml b/pnpm-workspace.yaml
index 1fc996e4c47..e5952498942 100644
--- a/pnpm-workspace.yaml
+++ b/pnpm-workspace.yaml
@@ -329,6 +329,7 @@ patchedDependencies:
   matrix-js-sdk@38.3.0: patches/matrix-js-sdk@38.3.0.patch
   ember-source: patches/ember-source.patch
   object-inspect: patches/object-inspect.patch
+  glimmer-scoped-css@0.8.1: patches/glimmer-scoped-css@0.8.1.patch
 allowBuilds:
   "@percy/core": true
   "@vscode/vsce-sign": true