I've not had this issue with my 2020 Rubicon yet, but it is a constant problem with my 2017 Ram pickup. I've had it since new, about 80,000 miles on it now . Never an issue the first few years, then the problem started. At first, a new battery in the fob cured the problem. Now a new battery only lasts about 2 weeks then the problems start up again. I've had all the same problems, key fob not detected, won't lock the doors, or unlock them, key fob has left the vehicle, etc. No pattern to when the codes show up and then disappear. Dealer has no clue.