A-Arm bolts falling out

[pjnagel]

Last year I noticed the right, lower, rear A-arm bolt was missing from my M8. I replaced the bolt and bushings. I also checked the rest of the bolts just to make sure no other ones were coming loose - they seemed fine.
This year I saw I was missing one on the left side. Why are these working loose and falling out?
Fortunately this hasn't caused any major issues, but I could imagine a ski flopping around sideways as I am cruising along at 50+MPH.

 

[ACMtnCat]

Typically the bolts don't come loose they shear off from hitting something solid with the spindle or snap from being over tightened. Double check them and make sure they aren't too tight. They have nylock nuts so they should not be able to come loose.