No Regen Braking While HV Battery Overheats?

I had my scangauge installed at the end of Oct 2014 so I haven't had the chance to use it in the summer. I have also done the the Intelligent Power Module (IPM) recall about 2 months ago. I have never noticed this issue before the hot weather.

When the weather gets hot, the regen gradually lowers the recovery amp. Normally it can regen at over -90 amps. As weather gets hot, it limits the regen to about -65 amps max. When it gets hotter, the regen lowers down to -35 amps max. I can feel the car not slowing down as quick as at -90 plus amps. When the car has been sitting under the 100f+ for a couple of hours, regen is completely at idle (less than -20Amps.) Mechanical brakes take over. The car feels the same as -30amp regen, HSI shows it is regen braking. However, scangauge shows idle regen (less than -20Amp) and the slowing down is done by mechanical brakes.

I don't know if this is the IPM recall's doing to protect itself from overheating. I can only speculate that the computer is protecting the hot battery until it cools down. If I turn on the AC at near full blast (7 bars) for 10 minutes to cool down the interior, the regen gradually returns. However, it never regens more than -70 amps.

Disregard the wheel noise. The dealer said it's the tires making the noise.