Improved tooltip in Redmine 4.1.0 ( #31441) causes a Javascript error on some (self-made) plugin pages using the "title" attribute.
This is caused by the absence of the tooltip() function in the "title" attribute. By inserting a judgment statement as follows, errors will not occured.

--- a/public/javascripts/application.js
+++ b/public/javascripts/application.js
@@ -998,13 +998,15 @@
 
 $(function () {
-    $('[title]').tooltip({
-        show: {
-          delay: 400
-        },
-        position: {
-          my: "center bottom-5",
-          at: "center top"
-        }
-    });
+    if ($('[title]').tooltip !== undefined) {
+        $('[title]').tooltip({
+            show: {
+              delay: 400
+            },
+            position: {
+              my: "center bottom-5",
+              at: "center top"
+            }
+        });
+    }
 });