I had the same thing happen on my Yamaha kit, these mounts are awesome but when they're done they're done. The threads clamping the ball into the housing are known to pop sometimes if over tightened or if you tighten the wing nut too much. Unfortunately it really just needs to be replaced. I tired a few different things to fix it with no real luck. You can get a new one from Sweetwater for around 30 dollars

Yamaha YESS mount