Noticed the same problem with our 85x, as in having to press the fob instead of keyless entry but wasn’t aware that it was the 12v battery.
The cold is definitely having a an effect , it was making SOS calls the other day when temps went below 0
Also our range has dropped significantly ,but thankfully we’re on cheap overnight electric.
In general though it’s been good since we picked it up in Feb. but not done too many miles.
We're on the train to Bangkok.