FWIW, there have been a few times when I have had entry and startup issues (with Entry & Drive). The first and second time it happened it scared the heck out of me. Car wouldn't unlock. Finally it unlocked when I put the key next to the drivers window and pushed the button. Then it wouldn't start until I put the key right up against the dash. The third time this happened I realized all 3 instances were in the same location. There's no obvious source of RF, but it must be environmental. Since then I've identified one other location near me that has a similar problem.

I had another time when they same thing kept happening in my garage, a location that had never had a problem before. This was about a week or so after I had changed the fob battery due to the car complaining it was low. So I changed the battery again, and the same issue reappeared after a few days. I had been using batteries I got from Ikea, which had been working fine in other stuff and well within the expiration date. The third time I tried a name brand (Sony I think) and all my problems disappeared. My guess is that the car complains that the battery is getting low when the voltage starts dropping. Perhaps it did not complain with the Ikea batteries because they could not provide the necessary current? In any case, it does appear the Entry & Drive is sensitive to the quality of the battery. But don't tell Porsche because they start making us buy Porsche-brand batteries at $45 each.