maybe a screw driver wedged in there from the small hole, find it hard to believe the plate is spinning tho. its got very little wiggle room and it like a 4x4 plate.

is the bolt loose enough where you can push the bolt up and feel it move up and down?

keep in mind the bolt is like 3 inches long too. last time out one of mine took the jack handle on the breaker bar for more then 1/2 way out. some very long 1/2 turns i tell ya took a while to get out.