Seems to be a recurring theme on flights to/from South America on multiple carriers, but the J cabin on 4M 4520 (EZE-MIA) was a virtual sauna on Sat/Sun. Same with the VIP lounge too for that matter. I did take a look at the temperature control on the 763 and it was set to max.

Is it just the luck of the draw or is that just how it is?