I downloaded 3.5.5 to both our Gravities last evening. This morning everything seemed fine with the green GDE (although I haven't driven it yet). But the black GDE would not respond to the key even though the key had worked flawlessly all day yesterday. I had to remove and reinsert the battery to get it working again.
Same! Key fob had been working OK (with the usual delays, warnings, etc.), but this morning, which was the first time I’d approached the car since the 3.3.5 update was installed, it didn’t recognize the key fob at all. Not via proximity or button presses. I just stood there dumbfounded. Of course I was running late for the gym. This always happens when I am in a rush
I went back into the house to get my key card, which DID work, but none of my key fob preferences or settings were applied. I obviously need to add the key card to my profile, but keep forgetting to do so. The car woke up and let me shift it into gear, but homelink wouldn’t respond to direct tapping on screen, nor programmable button presses. I was trapped in my garage

So I ran back into the house again and grabbed the garage door remote and was on my way (quite late).
I wish I’d thought to fiddle with the key fob battery. That may have helped me avoid the whole palaver. Sigh.
Interestingly, when I approached the car to drive home after the gym, it recognized the key fob. It took it several seconds to do so (whilst I stood next to the car), but it unlocked, all my profile prefs were activated, and it let me drive

And as an added bonus, as I approached my house, the programmable button press activated Home Link.