Flight crash due to current drop

while in autonmus flight after convertion from multerouter to fixedwing the current got dropped gradually in 5 to 8 seconds but the voltage remained same . what may the reason ?? the aircraft got crashed.
battery is 25C rating
temperature was 60 to 70 degree celcus

How are we supposed to guess what happened when you do not provide a .bin log file using something like wetransfer.com ?