diff --git a/lib/src/async_import_cache.dart b/lib/src/async_import_cache.dart
index 0deb6285f..f49fa8600 100644
--- a/lib/src/async_import_cache.dart
+++ b/lib/src/async_import_cache.dart
@@ -52,19 +52,21 @@ final class AsyncImportCache {
   /// The canonicalized URLs for each non-canonical URL that's resolved using a
   /// relative importer.
   ///
-  /// The map's keys have four parts:
+  /// The map's keys have five parts:
   ///
-  /// 1. The URL passed to [canonicalize] (the same as in [_canonicalizeCache]).
+  /// 1. The URL passed to [_canonicalize] (the same as in [_canonicalizeCache]).
   /// 2. Whether the canonicalization is for an `@import` rule.
-  /// 3. The `baseImporter` passed to [canonicalize].
-  /// 4. The `baseUrl` passed to [canonicalize].
+  /// 3. The `importer` passed to [_canonicalize].
+  /// 4. The `baseUrl` passed to [_canonicalize].
+  /// 5. The `resolveUrl` passed to [_canonicalize].
   ///
   /// The map's values are the same as the return value of [canonicalize].
   final _relativeCanonicalizeCache = <(
     Uri, {
     bool forImport,
-    AsyncImporter baseImporter,
-    Uri? baseUrl
+    AsyncImporter importer,
+    Uri? baseUrl,
+    bool resolveUrl
   }),
       AsyncCanonicalizeResult?>{};
 
@@ -153,18 +155,37 @@ final class AsyncImportCache {
           "in the browser.";
     }
 
-    if (baseImporter != null && url.scheme == '') {
-      var relativeResult = await putIfAbsentAsync(
-          _relativeCanonicalizeCache,
-          (
-            url,
-            forImport: forImport,
-            baseImporter: baseImporter,
-            baseUrl: baseUrl
-          ),
-          () => _canonicalize(baseImporter, baseUrl?.resolveUri(url) ?? url,
-              baseUrl, forImport));
-      if (relativeResult != null) return relativeResult;
+    if (url.scheme == '') {
+      if (baseImporter != null) {
+        var relativeResult = await putIfAbsentAsync(
+            _relativeCanonicalizeCache,
+            (
+              url,
+              forImport: forImport,
+              importer: baseImporter,
+              baseUrl: baseUrl,
+              resolveUrl: true
+            ),
+            () => _canonicalize(baseImporter, url, baseUrl, forImport,
+                resolveUrl: true));
+        if (relativeResult != null) return relativeResult;
+      }
+
+      for (var importer in _importers) {
+        var relativeResult = await putIfAbsentAsync(
+            _relativeCanonicalizeCache,
+            (
+              url,
+              forImport: forImport,
+              importer: importer,
+              baseUrl: baseUrl,
+              resolveUrl: false
+            ),
+            () => _canonicalize(importer, url, baseUrl, forImport));
+        if (relativeResult != null) return relativeResult;
+      }
+
+      return null;
     }
 
     return await putIfAbsentAsync(
diff --git a/lib/src/import_cache.dart b/lib/src/import_cache.dart
index e34f0a7ee..d63800135 100644
--- a/lib/src/import_cache.dart
+++ b/lib/src/import_cache.dart
@@ -5,7 +5,7 @@
 // DO NOT EDIT. This file was generated from async_import_cache.dart.
 // See tool/grind/synchronize.dart for details.
 //
-// Checksum: d157b83599dbc07a80ac6cb5ffdf5dde03b60376
+// Checksum: 6bdfe30b15772673fb523f03165a2f4f94544a46
 //
 // ignore_for_file: unused_import
 
@@ -54,19 +54,21 @@ final class ImportCache {
   /// The canonicalized URLs for each non-canonical URL that's resolved using a
   /// relative importer.
   ///
-  /// The map's keys have four parts:
+  /// The map's keys have five parts:
   ///
-  /// 1. The URL passed to [canonicalize] (the same as in [_canonicalizeCache]).
+  /// 1. The URL passed to [_canonicalize] (the same as in [_canonicalizeCache]).
   /// 2. Whether the canonicalization is for an `@import` rule.
-  /// 3. The `baseImporter` passed to [canonicalize].
-  /// 4. The `baseUrl` passed to [canonicalize].
+  /// 3. The `importer` passed to [_canonicalize].
+  /// 4. The `baseUrl` passed to [_canonicalize].
+  /// 5. The `resolveUrl` passed to [_canonicalize].
   ///
   /// The map's values are the same as the return value of [canonicalize].
   final _relativeCanonicalizeCache = <(
     Uri, {
     bool forImport,
-    Importer baseImporter,
-    Uri? baseUrl
+    Importer importer,
+    Uri? baseUrl,
+    bool resolveUrl
   }),
       CanonicalizeResult?>{};
 
@@ -153,17 +155,33 @@ final class ImportCache {
           "in the browser.";
     }
 
-    if (baseImporter != null && url.scheme == '') {
-      var relativeResult = _relativeCanonicalizeCache.putIfAbsent(
-          (
-            url,
-            forImport: forImport,
-            baseImporter: baseImporter,
-            baseUrl: baseUrl
-          ),
-          () => _canonicalize(baseImporter, baseUrl?.resolveUri(url) ?? url,
-              baseUrl, forImport));
-      if (relativeResult != null) return relativeResult;
+    if (url.scheme == '') {
+      if (baseImporter != null) {
+        var relativeResult = _relativeCanonicalizeCache.putIfAbsent(
+            (
+              url,
+              forImport: forImport,
+              importer: baseImporter,
+              baseUrl: baseUrl,
+              resolveUrl: true
+            ),
+            () => _canonicalize(baseImporter, url, baseUrl, forImport,
+                resolveUrl: true));
+        if (relativeResult != null) return relativeResult;
+      }
+
+      for (var importer in _importers) {
+        var relativeResult = _relativeCanonicalizeCache.putIfAbsent((
+          url,
+          forImport: forImport,
+          importer: importer,
+          baseUrl: baseUrl,
+          resolveUrl: false
+        ), () => _canonicalize(importer, url, baseUrl, forImport));
+        if (relativeResult != null) return relativeResult;
+      }
+
+      return null;
     }
 
     return _canonicalizeCache.putIfAbsent((url, forImport: forImport), () {