Ah yes, this reminds me of my University account. I chose a long password generated with my password manager, which of course contained a chara66 that was both allowed at set up and usage. But because I had to frequently type it in without my password manager (i.e. on a University PC), I wanted to change it. But the change dialog asked for the old password and didn't accept it, due to the forbidden character. I had to go to the support who refused to believe my story and wasn't able to change my password. It took a few weeks to get hold of a person who was allowed to change passwords.