What model and year RPOD do you have? Any idea how old the dome is?
Late model PODS have a 14mm keder rail. Some of the older PODS with rings have a 9mm keder rail.
It's doubtful you have the wrong one if both your POD and Dome were made over the last 4 or 5 years? I not exactly sure when FR switched form 9 to 14mm. Maybe 2011?
Anyway we have had several owners with the correct dome and rail still have spots where the dome would slip out. We boiled it down to an issue that flares up when sometimes during the keder rail installation the rail opens or spreads some. No big deal, the easy fix is to get a pair of vise grips, set the jaw and use to close the keder rail channel some. Easy Peazy. No problem.