diff -r 75abdd7f2568 roundup/cgi/templating.py
--- a/roundup/cgi/templating.py	Thu Jul 30 17:16:32 2026 -0400
+++ b/roundup/cgi/templating.py	Mon Aug 03 03:58:40 2026 +0000
@@ -3607,6 +3607,10 @@
     def __init__(self, client):
         self.client = client
         self._ = self.client._
+        self._bound_methods = {}
+        
+        for name, method in self.client.instance.templating_util_methods.items():
+            self._bound_methods[name] =  method.__get__(self)
 
     def Batch(self, sequence, size, start, end=0, orphan=0, overlap=0):
         return Batch(self.client, sequence, size, start, end, orphan,
@@ -3741,14 +3745,22 @@
 
     """
 
-    def __getattr__(self, name):
-        """Try the tracker's templating_utils."""
-        if not hasattr(self.client.instance, 'templating_utils'):
-            # backwards-compatibility
-            raise AttributeError(name)
-        if name not in self.client.instance.templating_utils:
-            raise AttributeError(name)
-        return self.client.instance.templating_utils[name]
+    def __getattribute__(self, name):
+        client = super().__getattribute__('client')
+
+        # a lot of client lookups are done, we already have it
+        # just return it.
+        if name == "client": return client
+
+        if (hasattr(client.instance, 'templating_utils') and
+            (name in client.instance.templating_utils) ):
+            return client.instance.templating_utils[name]
+
+        bound_methods = super().__getattribute__('_bound_methods')
+        if name in bound_methods:
+            return bound_methods[name]
+        
+        return super().__getattribute__(name)
 
     def keywords_expressions(self, request):
         return render_keywords_expression_editor(request)
diff -r 75abdd7f2568 roundup/instance.py
--- a/roundup/instance.py	Thu Jul 30 17:16:32 2026 -0400
+++ b/roundup/instance.py	Mon Aug 03 03:58:40 2026 +0000
@@ -59,6 +59,7 @@
         self.actions = {}
         self.cgi_actions = {}
         self.templating_utils = {}
+        self.templating_util_methods = {}
 
         libdir = os.path.join(self.tracker_home, 'lib')
         self.libdir = (os.path.isdir(libdir) and libdir) or ''
@@ -262,6 +263,17 @@
            instead.
 
         """
+        # prevent overriding of internal TemplatingUtil methods/vars.
+        if name.startswith('_') or name == "client":
+            import inspect
+            caller = inspect.stack()[1]
+            raise ValueError(
+                "Can't define template utility named '%(name)s' at:\n"
+                "   %(filename)s:%(lineno)d\n"
+                "   Utility method names must not start with '_' or "
+                " be called client.\n"
+                % {**caller._asdict(), "name": name})
+
         self.templating_utils[name] = function
 
     def registerUtilMethod(self, name, function):
@@ -275,9 +287,18 @@
            `self` is a TemplatingUtils object. You can use self.client
            to access the client object for your request.
         """
-        setattr(self.TemplatingUtils,
-                name,
-                function)
+        # prevent overriding of internal TemplatingUtil methods/vars.
+        if name.startswith('_') or name == "client":
+            import inspect
+            caller = inspect.stack()[1]
+            raise ValueError(
+                "Can't define template utility method named '%(name)s' at:\n"
+                "   %(filename)s:%(lineno)d\n"
+                "   Utility method names must not start with '_' or "
+                " be called client.\n"
+                % {**caller._asdict(), "name": name})
+
+        self.templating_util_methods[name] = function
 
 
 class TrackerError(RoundupException):