diff --git a/lib/timeline/Core.js b/lib/timeline/Core.js
index 995b3755ac..4c534e739c 100644
--- a/lib/timeline/Core.js
+++ b/lib/timeline/Core.js
@@ -287,6 +287,12 @@ class Core {
      */
     function onMouseScrollSide(event) {
       if (!me.options.verticalScroll) return;
+      
+      if (me._isProgramaticallyScrolled) {
+        me._isProgramaticallyScrolled = false;
+        return;
+      }
+      
       event.preventDefault();
       if (me.isActive()) {
         const adjusted = -event.target.scrollTop;
@@ -1355,7 +1361,7 @@ class Core {
       this.dom.left.parentNode.scrollTop = -this.props.scrollTop;
       this.dom.right.parentNode.scrollTop = -this.props.scrollTop;
     }
-
+    this._isProgramaticallyScrolled = true;
     return this.props.scrollTop;
   }