Maybe this new issue is for a new topic, maybe not, so anyway...
I noticed that if I enter member title that this is a some sort of a new rank, and not the old rank of a user from previous version of forum.
After I changed user's member_title in admin and after that checked in phpMyAdmin, the value 'member_title' in table 'core_members' was not changed. It is like Invision Community added a new table with ranks in DB.