More info... this is baffling me.
I emptied the recycle bin on the portal just in case the deleted modules were causing some kind of issue.
I can go into the Users table and change IsSuperUser to True for any user account in the portal with this issue and immediately they can go and edit anything and their login sticks properly.
Then when I change IsSuperUser back to false, the account works properly. The host menu disappears, etc, and the account is able to edit anything without being prompted for a login.
So, I log in as a host and under Host Settings, restart the application. The account now gets prompted to login at every edit, again.
Checked tab permissions on the Settings page and in the DB tables. Looks normal (All users View, and Administrators View and Edit).
Any ideas welcome...