[VoltsFRS2013]

Never had this issue (given I don't track the car, however, I have swapped my battery once.)

While installing those tie-downs, you have to make sure you are going equally on each side as you tighten down, otherwise, the tension from one will cause the other to pop out. Get them both in the hole and thread the nut down till both sides are equally hand tight, slowly tighten each side.

Also note, those tie-downs don't need to be extremely tight. If your hand cannot move the battery it is tight enough. The tighter those get, the more stress on the side of your battery. Batteries expand slightly overtime when they're hot. Not a good combination of things to have inside your engine bay.