The exposure issue won't be related to the heat or battery issue.
But if you upload an original jpg to Google drive and post a link, someone might be able to check to see what might have happened there.
It looks like you've almost gone to the...
Most likely the battery swelled and popped loose, instant power loss. At least that's my first thought. There's folks on here that could look over the flight data file and give you a better explanation I'm sure.
Some information on the battery that was in use could help with some form of answers. The M2 series battery doesn’t take much swelling to create a disconnect.