this is the exact System Alert I Get after 30 mins 50 mins of use and started happening a couple weeks ago. had to get the picture from another source because i never thought of taking a picture of it but this is the exact same message
I purchased my Quest 2 several weeks ago and had no problems at all, as soon as I applied the new update last weekend I can only have it on for approx 5 minutes when the audible alarm comes on and the overheating message tells me that the headset has to shut down. It is stored and played in an airconditioned room set at 23 Degrees C.
The support team told me they would get back to me within 48 to 72 hrs on the 22nd November, still waiting.