450i AP ground screws seizing? Too long?

Anybody else have trouble with the ground screws?  Both of them on this AP are seized.  I tried putting some anti-seize on the threads of one of them and unscrewing it, but of course anti-seize doesn't really work after the fact.

The screws (actually hex head bolts) appear to be 10 mm long, which seems pretty long for the depth of the material they are going into.  When I got it out, the last 4 mm or so of threads was filled with what looks like aluminum.  I'm wondering if the factory is using screws that are too long and using enough force that they are tapping themselves through the bottom of the housing and trying to go into the opposite side.

It is definitely ungood.