The first culprit i would try an nail down is the Battery. A bad or getting there battery causes all kinds of crazy things to happpen. Get the Battery properly tested and you will be on your way to finding out the problem if not solving it.
If it does not happen again then put it down to a Big Glitch, if it does, i would still start with the battery and check its cables, maybe one is loosening up. Next do a full deep scan on the vehicle through all four computer systems, B,C, P, and U. (Body, Chassis, Powertrain, Communications) and see if anything pops. At the temp you mentioned, that would qualify as a cool day in Arizona or La, or Texas where these vehicles do spend quite bit of time so the temp may not be a factor. See how it goes and let us know what you find, good luck
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