[12.0][FIX]web_timeline: fix group orders

web_timeline/static/src/js/timeline_view.js

@@ -166,7 +166,8 @@ odoo.define('web_timeline.TimelineView', function (require) {
             if (grp2.id === -1) {
                 return +1;
             }
-            return grp1.content - grp2.content;
+
+            return grp1.content.locateCompare(grp2.content);
 
         },