not crossthreaded. Williams unfortunately used locktite on the threads for most of the late 11B and 11C games.
Cyclone, Whirlwind, EATPM, Rollersgames will all do this when you shop them. I usually have around 8 or so do this, sometimes i'll luck out and have only a few and sometimes they all strip.
Use some channel locks or vice grips to hold the T-nut, sometimes you can wedge a large flat head screw driver in there. Other times nothing will work and you will have to snap off the screw.