Tried everything, Nickname will not change

Hello all. Like the subject says, I have searched the forums and tried multiple solutions. When I change my nickname, whether in the bookmarks manager, identity, options, it’ll switch for 1 second then reset back to my personal name, which I do not want showing. I try disconnecting and reconnecting but it goes back to my personal name every time, even if I have the nickname filled in. Anybody else have this issue or know a solution to this? Thanks!

Have you tried it only on one Server? Or is the bug also occurring on other Server?

Did you try disabling “Automatically update nickname in bookmark” in Tools -> Options -> Application?
Can you edit other settings and are they still the same after restarting the application?
Are you running the client multiple times?
Check the log files after this happens as well and see if there are any entries