I discovered this problem 2 years ago and it is still not fixed.
When registering an account, you can use words that I will not mention in public, but I will mention them in private messages for staff.
These words are not bypasses, but they cannot be used on their own, so additional random words are used, but no other characters are involved that affect filtering.
I hope I get more information on this and if it is possible to find out if this is expected behavior because the problem has not been fixed for a long time.
A private message is associated with this bug report