Lexus ES 2007-12 :: Key Fob And Lock Button Inside Stopped Locking The Doors

2010 ES350, 84,000 miles. I have seen many threads on door locking/unlocking issues but none quite like mine that I've been able to locate. The key fob stopped locking the doors a few weeks ago, neither will the lock button on the drivers door inside the car. No sounds, beeps, lights or mechanical attempts to lock the doors. There are no indicator lights or messages suggesting an issue.

I can go around and manually lock all the doors, hit the lock on the key fob, and the car will beep and light up as if the locks worked fine. I also manually locked each door separately and in all combinations, the only combination which will enable the beep as if the door locks work with the fob is if they are all locked. The fob will unlock the doors however, unlocking has not been an issue.

My first attempt to correct was to disconnect the battery for a few minutes, reconnect and they worked fine for a week or so. The next time, with all the same symptoms, disconnecting the battery did nothing, the fob, however did start working a day or two later. The third time it happened we took the car directly to the dealership who has had it for 5 days and have been unable to identify an issue (the fob started to work on day 3).