Check the trigger spring. The bitch one to get in place where one end of it sits in a little hole of the mechbox and the other end sits on the trigger. It either might not be seated in the hole (basically pinned/squished inbetween the trigger and the inside of the shell) or if it's somehow reversed so the long leg of it is sticking out too far it get's in the way of the selector plate. The prong sticks out of the mechbox's left side and jams/gouges the plate as it moves. I'd look there first (don't even need to crack the mech open).
I've got too G36 mechboxes on the bench right now...but won't be able to check anything until Sun night, sorry.
Tys
|