diff --git a/readme.txt b/readme.txt
index 5d77ddc24..c013aefee 100644
--- a/readme.txt
+++ b/readme.txt
@@ -259,6 +259,7 @@ You can report security bugs through the Patchstack Vulnerability Disclosure Pro
 
 = 8.0 - Coming soon 2026 =
 * 🌱**OptiMax** OptiMax to maximize the page score.
+* **Optimize** Fixed JS Delay mode not executing `load` event listeners. (#629)
 
 = 7.9 - Aug 5 2026 =
 * **Cloud** Changed Health service to run asynchronously, resuming through WP cron when the cloud defers the request.
diff --git a/src/optimize.cls.php b/src/optimize.cls.php
index 8b50f0d63..ce1557a52 100644
--- a/src/optimize.cls.php
+++ b/src/optimize.cls.php
@@ -88,15 +88,14 @@ public function init() {
 		if ($this->cfg_js_defer == 2) {
 			add_filter(
 				'litespeed_optm_cssjs',
-				function ( $con, $file_type ) {
-					if ($file_type == 'js') {
-						$con = str_replace('DOMContentLoaded', 'DOMContentLiteSpeedLoaded', $con);
-						// $con = str_replace( 'addEventListener("load"', 'addEventListener("litespeedLoad"', $con );
+				function ( $con, $file_type, $src ) {
+					if ($file_type == 'js' && !Utility::str_hit_array($src, $this->cfg_js_defer_exc)) {
+						$con = $this->_replace_js_events( $con );
 					}
 					return $con;
 				},
 				20,
-				2
+				3
 			);
 		}
 
@@ -1005,8 +1004,8 @@ private function _js_inline_defer( $con, $attrs = false, $minified = false ) {
 		if ($this->cfg_js_defer === 2) {
 			// Drop type attribute from $attrs
 			$attrs = Utility::remove_attr( $attrs, 'type' );
-			// Replace DOMContentLoaded
-			$con = str_replace('DOMContentLoaded', 'DOMContentLiteSpeedLoaded', $con);
+			// Replace DOMContentLoaded and load event listeners
+			$con = $this->_replace_js_events( $con );
 			return '<script' . $attrs . ' type="litespeed/javascript">' . $con . '</script>';
 			// return '<script' . $attrs . ' type="litespeed/javascript" src="data:text/javascript;base64,' . base64_encode( $con ) . '"></script>';
 			// return '<script' . $attrs . ' type="litespeed/javascript">' . $con . '</script>';
@@ -1015,6 +1014,22 @@ private function _js_inline_defer( $con, $attrs = false, $minified = false ) {
 		return '<script' . $attrs . ' src="data:text/javascript;base64,' . base64_encode($con) . '" defer></script>';
 	}
 
+	/**
+	 * Replace JS DOMContentLoaded and load event listeners for JS Delay mode
+	 *
+	 * @since  8.0
+	 */
+	private function _replace_js_events( $con ) {
+		if ( empty( $con ) || ! is_string( $con ) ) {
+			return $con;
+		}
+
+		$con = str_replace( 'DOMContentLoaded', 'DOMContentLiteSpeedLoaded', $con );
+		$con = preg_replace( '/(?<!\.)\b(window\.|document\.)?addEventListener\(\s*([\'"])load\2/', '$1addEventListener($2DOMContentLiteSpeedLoaded$2', $con );
+		$con = preg_replace( '/((?:\$|jQuery)\(\s*(?:window|document)\s*\)\s*\.on\(\s*)([\'"])load(?=[.\s\'"])/', '$1$2DOMContentLiteSpeedLoaded', $con );
+		return $con;
+	}
+
 	/**
 	 * Replace ESI to JS inline var (mainly used to avoid nonce timeout)
 	 *