closes #3621

public/src/client/topic.js

@@ -247,6 +247,11 @@ define('forum/topic', [
 			}
 
 			if (newUrl !== currentUrl) {
+				if (Topic.replaceURLTimeout) {
+					clearTimeout(Topic.replaceURLTimeout);
+				}
+				Topic.replaceURLTimeout = setTimeout(function() {
+					Topic.replaceURLTimeout = 0;
 					if (history.replaceState) {
 						var search = (window.location.search ? window.location.search : '');
 						history.replaceState({
@@ -254,6 +259,7 @@ define('forum/topic', [
 						}, null, window.location.protocol + '//' + window.location.host + RELATIVE_PATH + '/' + newUrl + search);
 					}
 					currentUrl = newUrl;
+				}, 500);
 			}
 		}
 		return index;