diff --git a/devtools/server/actors/highlighters/css-grid.js b/devtools/server/actors/highlighters/css-grid.js
index bc332d5887ae..a3b4ebbaf40c 100644
--- a/devtools/server/actors/highlighters/css-grid.js
+++ b/devtools/server/actors/highlighters/css-grid.js
@@ -33,9 +33,6 @@ const {
   getWindowDimensions,
   setIgnoreLayoutChanges,
 } = require("resource://devtools/shared/layout/utils.js");
-const {
-  stringifyGridFragments,
-} = require("resource://devtools/server/actors/utils/css-grid-utils.js");
 loader.lazyGetter(this, "HighlightersBundle", () => {
   return new Localization(["devtools/shared/highlighters.ftl"], true);
 });
@@ -626,16 +623,24 @@ class CssGridHighlighter extends AutoRefreshHighlighter {
    * The AutoRefreshHighlighter's _hasMoved method returns true only if the
    * element's quads have changed. Override it so it also returns true if the
    * element's grid has changed (which can happen when you change the
-   * grid-template-* CSS properties with the highlighter displayed).
+   * grid-template-* CSS properties with the highlighter displayed). This
+   * check is prone to false positives, because it does a direct object
+   * comparison of the first grid fragment structure. This structure is
+   * generated by the first call to getGridFragments, and on any subsequent
+   * calls where a reflow is needed. Since a reflow is needed when the CSS
+   * changes, this will correctly detect that the grid structure has changed.
+   * However, it's possible that the reflow could generate a novel grid
+   * fragment object containing information that is unchanged -- a false
+   * positive.
    */
   _hasMoved() {
     const hasMoved = AutoRefreshHighlighter.prototype._hasMoved.call(this);
 
-    const oldGridData = stringifyGridFragments(this.gridData);
+    const oldFirstGridFragment = this.gridData?.[0];
     this.gridData = this.currentNode.getGridFragments();
-    const newGridData = stringifyGridFragments(this.gridData);
+    const newFirstGridFragment = this.gridData[0];
 
-    return hasMoved || oldGridData !== newGridData;
+    return hasMoved || oldFirstGridFragment !== newFirstGridFragment;
   }
 
   /**
diff --git a/devtools/server/actors/utils/css-grid-utils.js b/devtools/server/actors/utils/css-grid-utils.js
index 59b8898b8cd3..9631dcd80062 100644
--- a/devtools/server/actors/utils/css-grid-utils.js
+++ b/devtools/server/actors/utils/css-grid-utils.js
@@ -19,20 +19,6 @@ function getStringifiableFragments(fragments = []) {
   return fragments.map(getStringifiableFragment);
 }
 
-/**
- * Returns a string representation of the CSS Grid data as returned by
- * node.getGridFragments. This is useful to compare grid state at each update and redraw
- * the highlighter if needed. It also seralizes the grid fragment data so it can be used
- * by protocol.js.
- *
- * @param  {Object} fragments
- *         Grid fragment object.
- * @return {String} representation of the CSS grid fragment data.
- */
-function stringifyGridFragments(fragments) {
-  return JSON.stringify(getStringifiableFragments(fragments));
-}
-
 function getStringifiableFragment(fragment) {
   return {
     areas: getStringifiableAreas(fragment.areas),
@@ -72,4 +58,3 @@ function getStringifiableTrack({ breadth, start, state, type }) {
 }
 
 exports.getStringifiableFragments = getStringifiableFragments;
-exports.stringifyGridFragments = stringifyGridFragments;