Your CURR.Vcc drops precipitously at the end of your flight. In fact, it
falls off a cliff to below 4.7V. Your PixHawk is not going to like that at all. That sort of drop would certainly explain PixHawk stopping.
Also. Turn on arming checks.
"name" : "Truncated Log",
"results" : [
{
"evidence" : [
"Final altitude 573.390015 metres",
"Takeoff altitude 556.969971 metres",
"Final relative altitude 16.420044 metres",
"Vehicle still flying",
"Low AutoPilot Voltage (4.00 < 4.60"
],
Assuming you only have one battery on board - yes, it comes from the LiPO, probably via a BEC or power brick.
The simplest way to avoid this is to enable (and configfure correctly!) the battery failsafe. I can see that it is currently misconfigured - you are flying on 6S and the FS_BATT_VOLT is 10.5 - suitable for a 3S setup.