I don't have autofeed happen often and it certainly gets hot here especially outside. It gets >150F in closed car most sunny days most months during year here, too. Most auto feeding I have had is with 801 attys on 801 Woodvils, especially with the new shorter catchcups on the newer Woodvil (Post old style Woody). Way, way back some of us played with 801 attys on 510 connection using adapter (or was it the other way around....

). Oh yeah it was 801 on 510 because we were playing with IKV short attys. I had pretty regular auto feeding doing that. I would set it down at night and within a few hours the catchcup was over flowing and would keep running out so it wasn't just the juice settling and coming out from the excess juice is generous sized atty.
I generally use 30/70 to 50/50 PG/VG and few issues. DH flies out of town work every week (normal high altitude commercial airlines). He has no issues with REO self feeding in his pocket
but he uses Resurector Cartos. On rare occasions he did have a mess when he had REO, with full bottle, and atty/carto, in baggie, squashed into his carry on bag. That has been very rare, though.
If I'm going to be leaving REO(s) in car for a few hours, when temps get so hot in car, I like to carry an insulated small, soft side lunch bag with a blue ice in it to store the REOs, juice, and a few personal items that don't do well with repeated exposure to high temps (chapstick, makeup, meds, etc.) (DH used to carry a 12 pack of Pepsi Max behind his car seat. Ocassionally one would burst from heat in parked car. We have pretty heavy tinting and always use a windshield sun screen, too.)
Feisty Alice