When cb_login uses a wrong Itemid then the problem is that there are two menu links to uddeIM in the database and cb_login uses the wrong one.
Please check if you have created only ONE menu link and check if you have not a orphaned link in the trash (empty the trash, remember to switch to the correct view).
I have checked some Joomla configurations in the past to ensure that it is not a bug in uddeIM and it was ALWAYS a mistake in the configuration.
In most cases it was the Itemid (because of two or more links), sometimes a wrong live_path and so.
uddeIM & uddePF Development
CB Language Workgroup
CB 3rd Party Developer
This overwrites also the Itemid when the caller uses a wrong Itemid. I do not know if index.php filters this, so it might have no effect but you can give it a try.
It does not fix the problem but may fixes the symptoms.
uddeIM & uddePF Development
CB Language Workgroup
CB 3rd Party Developer