To prevent your rear coil springs from coming unseated or pop out, consider the Zone Offroad rear coil retainer clip kit. The kit includes both axle and frame side retainers so you are assured the rear coils stay in place.
The JK Wrangler doesn't allow for much added droop travel because the bump stops are not inside the coil like on a TJ to keep the coils centered on the mounts. Depending on the suspension kit or combination of parts being used, this problem can be accentuated. Some kits maximize travel with longer shocks, but if not matched to the correct coil or coil spacer height, this problem becomes evident. If you are experiencing this problem, Zone Offroad offers this JK Coil Retainer Kit as a solution.