it all depends on the specific mounts obviously - but if its got a retaining 'nut' on one side it could be that this is pushed out of the hole a bit.
I also happened to come across this specific to a Bogen review:
Quote: This is due to the knobs that lock the legs. Somehow the connection of the plastic knobs to the metal screws are weak and if you twist the knobs a bit hard, it will slip. Same thing goes for the ball head locking levers also. (They should have used an all metal knob or designed a better plastic to screw connection.) Because of this I'm hesitant to tighten reallly hard since I dont want to damage the knobs.
No idea on the specific Bogen you have though - and I'm simply guessing...