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diff --git a/testing/web-platform/tests/css/css-scroll-anchoring/heuristic-with-offset-update-from-scroll-event-listener.html b/testing/web-platform/tests/css/css-scroll-anchoring/heuristic-with-offset-update-from-scroll-event-listener.html
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+++ b/testing/web-platform/tests/css/css-scroll-anchoring/heuristic-with-offset-update-from-scroll-event-listener.html
@@ -0,0 +1,59 @@
+<!doctype html>
+<meta charset="utf-8">
+<link rel="help" href="https://drafts.csswg.org/css-scroll-anchoring-1/">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1586909">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<link rel="author" title="Mozilla" href="https://mozilla.org">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+  #scroller {
+    overflow: scroll;
+    height: 500px;
+    height: 500px;
+  }
+  #before {
+    height: 200px;
+  }
+  #anchor {
+    position: relative;
+    width: 200px;
+    height: 200px;
+    margin-bottom: 500px;
+    background-color: blue;
+    top: 0px;
+  }
+</style>
+<div id="scroller">
+  <div id="before">
+  </div>
+  <div id="anchor">
+  </div>
+</div>
+<script>
+async_test(t => {
+  let scroller = document.querySelector('#scroller');
+  let before = document.querySelector('#before');
+  let anchor = document.querySelector('#anchor');
+
+  scroller.onscroll = t.step_func(function() {
+    // Adjust the 'top' of #anchor, which should trigger a suppression
+    anchor.style.top = '10px';
+
+    // Expand #before and make sure we don't apply an adjustment
+    before.style.height = '300px';
+
+    assert_equals(scroller.scrollTop, 200);
+
+    t.step_timeout(t.step_func_done(function() {
+      // Expand #before again and make sure we don't keep #anchor as
+      // an anchor from the last time.
+      before.style.height = '600px';
+      assert_equals(scroller.scrollTop, 200);
+    }), 0);
+  });
+
+  // Scroll down to select #anchor as a scroll anchor
+  scroller.scrollTop = 200;
+}, 'Positioned ancestors with dynamic changes to offsets trigger scroll suppressions.');
+</script>