I'm thinking somebody probably put a dab of loctite on the screw so it wouldn't work loose and that's what helped strip out the screw head. Years ago I was tryna take the radome off an AGM-88 HARM guidance assembly and had to call China Lake and ask them about it. Guy said they loctite them in and before you try to remove the screw, take a thin soldering iron tip and heat up the head by putting the tip at the cross point. Did that and the screw backed right out even being partially stripped.
