Same thing happened to me when I moved from Florida to Atlanta. My Orgin 8 cranks are all wacky now.

Do you have a square taper BB and crank? Does the crank become loose again no matter how tight you seem to tighten it?

I think I've heard it is possible that the square hole of the crank can round off slightly messing with the fit of the crank to BB. Dunno about the chainring bolts though.