[KennyP]

Yeah its recommended to replace that battery regularly or dont use it as keyless and put it in the slot if any first signs of low battery come up.

I once had an issue.
Entered the car using keyless... put my fob to the center console cubby thingy.
While driving got a message saying that no key is recognized for a moment.
Took that fob from the center console and moved it around a bit in the car and that message went away. Did not really think of it much and went on and drove to a carwash. Left my fob in the center console like before and got out to wash the car (it was that selfservice type of carwash).
While washing the car that key was not recognized again in the car interior and car locked itself. Usually you cant lock it if a key is still inside the car but with low battery it would not see it and allow locking through the door handle touch.
So finished washing my car and wanted to leave. Well, car would not unlock. Key inside, my phone on the passenger seat and spare key was in my luggage in the trunk. Had to leave my car to the car wash blocking others from using it, walk to the car dealer near the carwash, have them call me roadside assistance, wait 45 minutes to an hour for the assistance to arrive and break in to my car and unlock my doors. Image if that happened somewhere remote like in the forest or something.

While waiting for assistance, bought a new battery from a nearby gasstation and replaced it right after getting access my cars interior again. And never had any issues again.

So if you see any signs of key not being recognized, be aware and replace battery right away. And maybe put it in the key slot to be sure its recognized.