6
Ok - I'd recommend you turn on debug and look at the MySQL queries in debug to see if that leads you in the right direction.
The other thing to try is to look a the value of $types in the Smarty template debug information.
Hopefully one of these will lead you in the right direction. I don't use newbb on any of my sites (including my debug site) right now so I found the bug above by code inspection. There's probably something else that assumes $status is a string... looks like allowing "multiple" types was added somewhere along the way and by irmtfan after initial development.