We haven't heard of this happening before. 32 C is pretty warm and it could have been a temporary overheating of the iPad. Map Pilot, along with most drone related apps, is working pretty hard to provide the video feed and even when it isn't that warm out it the device can get warm. Our more northern users have complimented us on using their device as a hand warmer for them while they are standing around mapping...
Technically the camera shouldn't have been point at the horizon on the way to the beginning of the flight path at all so it is likely that something else was already going on.
You did all the right things. It sounds like there was an error either in the device itself or the aircraft. It could be Map Pilot, but for the most we are just receiving data at that point.
Please be sure to let us know if it happens again.