diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4ef780e40..a637d0352 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,6 +23,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Update types to work with `Node16` module resolution ([#12097](https://github.com/tailwindlabs/tailwindcss/pull/12097))
 - Don’t crash when important and parent selectors are equal in `@apply` ([#12112](https://github.com/tailwindlabs/tailwindcss/pull/12112))
 - Eliminate irrelevant rules when applying variants ([#12113](https://github.com/tailwindlabs/tailwindcss/pull/12113))
+- Improve RegEx parser, reduce possibilities as the key for arbitrary properties ([#12121](https://github.com/tailwindlabs/tailwindcss/pull/12121))
 
 ## [3.3.3] - 2023-07-13
 
diff --git a/src/lib/defaultExtractor.js b/src/lib/defaultExtractor.js
index c56597e92..5d63ef653 100644
--- a/src/lib/defaultExtractor.js
+++ b/src/lib/defaultExtractor.js
@@ -12,10 +12,12 @@ export function defaultExtractor(context) {
     let results = []
 
     for (let pattern of patterns) {
-      results = [...results, ...(content.match(pattern) ?? [])]
+      for (let result of content.match(pattern) ?? []) {
+        results.push(clipAtBalancedParens(result))
+      }
     }
 
-    return results.filter((v) => v !== undefined).map(clipAtBalancedParens)
+    return results
   }
 }
 
@@ -34,7 +36,7 @@ function* buildRegExps(context) {
     // This is a targeted fix to continue to allow theme()
     // with square brackets to work in arbitrary properties
     // while fixing a problem with the regex matching too much
-    /\[[^\s:'"`]+:[^\s]+?\[[^\s]+\][^\s]+?\]/,
+    /\[[^\s:'"`\]]+:[^\s]+?\[[^\s]+\][^\s]+?\]/,
 
     // Utilities
     regex.pattern([