How do you monitor your battery temperature?The air conditioning system can be used to chill the battery.
I have noticed this at very high outside temperature (>30C, high for the UK)
From the GTE service manual, if the battery exceeds 43C, the active cooling will be engaged.
In 25C weather I had the battery up to 39C after charging (This will run Stage 1 cooling which only uses the radiator and pumps)
It will use more electricity, but the battery will be able to charge faster as a result. If you turn the charge current way down in the infotainment, the pack won't heat up enough to necessitate charging.
Did you have a departure time set by mistake?I put my Mk8 GTE on charge today. Happened to be walking past a couple of hours later to hear the loud humming of the air conditioning working. Why would car decide to randomly turn on the air conditioning whilst charging? Such a waste of electricity!