Redmine

Hi - it seems that this framework fails when signing up with a "plus addressed" email address, (e.g. john_doe+324jgj@example.com).
I want to register a plus addressed email for the tvheadend.org forum which uses this framework.
It "seems" to work as in you get the registration emails, but when you try to login with the username/password it says wrong password, even though it definitely is not.
Tried the same when registering here on redmine and get exactly the same problem.
Is this a bug? Please can you prioritise a fix?
Thanks!