diff --git a/CHANGELOG.md b/CHANGELOG.md
index fa4292529979..9cda3d3e5dec 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,7 +8,7 @@ All notable changes to this project will be documented in this file.
 
 - Allow querying `views_per_visit` with a time dimension in Stats API
 - Add `bounce_rate` to page-filtered Top Stats even when imports are included, but render a metric warning about imported data not included in `bounce_rate` tooltip.
-- Add `time_on_page` to page-filtered Top Stats even when imports are included, unless legacy time on page is in view. 
+- Add `time_on_page` to page-filtered Top Stats even when imports are included, unless legacy time on page is in view.
 - Adds team_id to query debug metadata (saved in system.query_log log_comment column)
 - Add "Unknown" option to Countries shield, for when the country code is unrecognized
 - Add "Last 24 Hours" to dashboard time range picker and Stats API v2
@@ -19,6 +19,7 @@ All notable changes to this project will be documented in this file.
 
 - Keybind hints are hidden on smaller screens
 - Site index is sortable alphanumerically and by traffic
+- Use ResizeObserver instead of polling in tracker for scroll depth. Removes forced reflows caused by the tracker script.
 
 ### Fixed
 
diff --git a/tracker/package.json b/tracker/package.json
index ec0a47654a29..8e15e9d138a4 100644
--- a/tracker/package.json
+++ b/tracker/package.json
@@ -1,5 +1,5 @@
 {
-  "tracker_script_version": 33,
+  "tracker_script_version": 34,
   "type": "module",
   "scripts": {
     "lint": "eslint",
diff --git a/tracker/src/engagement.js b/tracker/src/engagement.js
index fcc302169e1a..f74e51694a44 100644
--- a/tracker/src/engagement.js
+++ b/tracker/src/engagement.js
@@ -137,10 +137,8 @@ function getDocumentHeight() {
 }
 
 function getCurrentScrollDepthPx() {
-  var body = document.body || {}
-  var el = document.documentElement || {}
-  var viewportHeight = window.innerHeight || el.clientHeight || 0
-  var scrollTop = window.scrollY || el.scrollTop || body.scrollTop || 0
+  var viewportHeight = window.innerHeight
+  var scrollTop = window.scrollY
 
   return currentDocumentHeight <= viewportHeight
     ? currentDocumentHeight
@@ -151,23 +149,11 @@ export function init() {
   currentDocumentHeight = getDocumentHeight()
   maxScrollDepthPx = getCurrentScrollDepthPx()
 
-  window.addEventListener('load', function () {
+  new ResizeObserver(function () {
     currentDocumentHeight = getDocumentHeight()
-
-    // Update the document height again after every 200ms during the
-    // next 3 seconds. This makes sure dynamically loaded content is
-    // also accounted for.
-    var count = 0
-    var interval = setInterval(function () {
-      currentDocumentHeight = getDocumentHeight()
-      if (++count === 15) {
-        clearInterval(interval)
-      }
-    }, 200)
-  })
+  }).observe(document.documentElement)
 
   document.addEventListener('scroll', function () {
-    currentDocumentHeight = getDocumentHeight()
     var currentScrollDepthPx = getCurrentScrollDepthPx()
 
     if (currentScrollDepthPx > maxScrollDepthPx) {
diff --git a/tracker/src/plausible.js b/tracker/src/plausible.js
index f8b669c7c2a8..51ab1fa7c7b5 100644
--- a/tracker/src/plausible.js
+++ b/tracker/src/plausible.js
@@ -16,7 +16,9 @@ function init(overrides) {
 
   initConfig(options)
 
-  initEngagementTracking()
+  if (!COMPILE_COMPAT) {
+    initEngagementTracking()
+  }
 
   if (!COMPILE_MANUAL || (COMPILE_CONFIG && config.autoCapturePageviews)) {
     initAutocapture(track)