After I upgraded my forum to 1.5 (1.5.0.beta2) one of the users started to have problem logging in. When he tries to login he sees “unknown error” but I found the error in the logs.
RecordInvalid (Validation failed: Username must not contain a sequence of 2 or more special chars (.-_))
(His/her username is “4__”)
Is there a solution for this issue?