Joomla 4.4.9 | SPPB Pro Version: 5.4.1

I updated SPPB Pro today from Version: 5.4.0 to Version: 5.4.1 and now I see this error when I try edit any page rom the back end;

Unhandled Runtime Error
TypeError: Cannot read properties of undefined (reading 'call')

Please open the browser console for more information!

Call Stack
l
(2:1375345)

4805
(2:6578)

Function.l
(2:1375345)

Browser console errors:

TypeError: Cannot read properties of undefined (reading 'call')...
VM312:2 Uncaught (in promise) SyntaxError: Unexpected token '<', "
    <!doctype "... is not valid JSON
Unchecked runtime.lastError: The message port closed before a response was received.
Unchecked runtime.lastError: The message port closed before a response was received.

I can edit fron the front end. Cleared cache etc.

Bro