diff --git a/components/script/dom/characterdata.rs b/components/script/dom/characterdata.rs
index 65c84f1e2c0..1222084edd5 100644
--- a/components/script/dom/characterdata.rs
+++ b/components/script/dom/characterdata.rs
@@ -70,6 +70,16 @@ impl CharacterData {
     fn content_changed(&self) {
         let node = self.upcast::<Node>();
         node.dirty(NodeDamage::OtherNodeDamage);
+
+        // If this is a Text node, we might need to re-parse (say, if our parent
+        // is a <style> element.) We don't need to if this is a Comment or
+        // ProcessingInstruction.
+        if self.is::<Text>() {
+            if let Some(parent_node) = node.GetParentNode() {
+                let mutation = ChildrenMutation::ChangeText;
+                vtable_for(&parent_node).children_changed(&mutation);
+            }
+        }
     }
 }
 
@@ -87,16 +97,6 @@ impl CharacterDataMethods for CharacterData {
         self.content_changed();
         let node = self.upcast::<Node>();
         node.ranges().replace_code_units(node, 0, old_length, new_length);
-
-        // If this is a Text node, we might need to re-parse (say, if our parent
-        // is a <style> element.) We don't need to if this is a Comment or
-        // ProcessingInstruction.
-        if self.is::<Text>() {
-            if let Some(parent_node) = node.GetParentNode() {
-                let mutation = ChildrenMutation::ChangeText;
-                vtable_for(&parent_node).children_changed(&mutation);
-            }
-        }
     }
 
     // https://dom.spec.whatwg.org/#dom-characterdata-length
diff --git a/tests/wpt/metadata/MANIFEST.json b/tests/wpt/metadata/MANIFEST.json
index 32fd7e9e58e..89e0a1b5f3a 100644
--- a/tests/wpt/metadata/MANIFEST.json
+++ b/tests/wpt/metadata/MANIFEST.json
@@ -154981,6 +154981,18 @@
      {}
     ]
    ],
+   "css/cssom/stylesheet-replacedata-dynamic.html": [
+    [
+     "/css/cssom/stylesheet-replacedata-dynamic.html",
+     [
+      [
+       "/css/cssom/stylesheet-replacedata-dynamic-ref.html",
+       "=="
+      ]
+     ],
+     {}
+    ]
+   ],
    "css/filter-effects/css-filters-animation-blur.html": [
     [
      "/css/filter-effects/css-filters-animation-blur.html",
@@ -253079,6 +253091,11 @@
      {}
     ]
    ],
+   "css/cssom/stylesheet-replacedata-dynamic-ref.html": [
+    [
+     {}
+    ]
+   ],
    "css/cssom/stylesheet-same-origin.css": [
     [
      {}
@@ -511223,6 +511240,14 @@
    "875598ca4271d4adaa11fbb01981b290e6235019",
    "testharness"
   ],
+  "css/cssom/stylesheet-replacedata-dynamic-ref.html": [
+   "e733dc40a41b899ab6c184211d75def5e52af3d4",
+   "support"
+  ],
+  "css/cssom/stylesheet-replacedata-dynamic.html": [
+   "defc259c76eb8ab8b7e3c6ad90951bf4c6f18ab3",
+   "reftest"
+  ],
   "css/cssom/stylesheet-same-origin.css": [
    "268fb9a72d33b3d18bbb82aaaac48bb15c89a88e",
    "support"
diff --git a/tests/wpt/web-platform-tests/css/cssom/stylesheet-replacedata-dynamic-ref.html b/tests/wpt/web-platform-tests/css/cssom/stylesheet-replacedata-dynamic-ref.html
new file mode 100644
index 00000000000..bc9cadebf15
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/cssom/stylesheet-replacedata-dynamic-ref.html
@@ -0,0 +1,7 @@
+<!doctype html>
+<title>(Ref #1) CSS Test Reference</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@mozilla.com">
+<link rel="author" title="Cheng You Bai" href="mailto:cyb.ai.815@gmail.com">
+<link rel="help" href="https://dom.spec.whatwg.org/#dom-characterdata-replacedata">
+<style>.pass { color: green }</style>
+<div class="pass">Should be green</div>
\ No newline at end of file
diff --git a/tests/wpt/web-platform-tests/css/cssom/stylesheet-replacedata-dynamic.html b/tests/wpt/web-platform-tests/css/cssom/stylesheet-replacedata-dynamic.html
new file mode 100644
index 00000000000..3ee5937c959
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/cssom/stylesheet-replacedata-dynamic.html
@@ -0,0 +1,12 @@
+<!doctype html>
+<title>(Test #1) CSS Test: Dynamic changes to the stylesheet contents using replaceData are reflected</title>
+<link rel="match" href="stylesheet-replacedata-dynamic-ref.html">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@mozilla.com">
+<link rel="author" title="Cheng You Bai" href="mailto:cyb.ai.815@gmail.com">
+<link rel="help" href="https://dom.spec.whatwg.org/#dom-characterdata-replacedata">
+<style>.fail { color: green }</style>
+<div class="pass">Should be green</div>
+<script>
+  document.body.offsetTop;
+  document.querySelector('style').firstChild.replaceData(1, 4, "pass");
+</script>
\ No newline at end of file
