Just a guess but it sounds like an "iced up" condenser. That is a phenomenon where it's so hot and humid out and you are in recycle mode , so that only very cool air (vs hot outer air) is being cycled. On the fully blue (cold) setting the condenser can actually ice up and block the flowing air from cooling off the freon. Especially @ low driving speeds.
In temps over 90*, try turning up the blue temp setting just a little, and/or use the 2nd or 3rd fan speed or higher, only in the normal mode (not recirculate.) I never use my auto A/C at max cold setting AND lowest fan speed. If I'm right, problem solved. I've had this happen on both my cars and home window A/C units.
Good luck!
MM
In temps over 90*, try turning up the blue temp setting just a little, and/or use the 2nd or 3rd fan speed or higher, only in the normal mode (not recirculate.) I never use my auto A/C at max cold setting AND lowest fan speed. If I'm right, problem solved. I've had this happen on both my cars and home window A/C units.
Good luck!
MM