Plz help with an autopilot crash

So my custom built hexacopter crashed during an autopilot flight. This was after two successful autopilot missions on the same day. Everything seemed to be working fine. I am running a pixhawk with 3.3? firmware I think (I updated it about 2 weeks ago). Missions were planned and executed on a Nexus 7 tablet with 3DR telemetry. I never touched the transmitter.

Checking the bin file, the only odd thing I noticed was a change in the throttle input on the “Battery Issues” plot. I never touched the throttle. I did lose the telemetry signal during all of the missions, but it didn’t affect anything on the other two flights. Also there were changes to Loiter and Stabilize modes that I never initiated.

Here is a video of the crash. Note the beeps just before the crash.

The pic from DroneShare is odd too. Not sure why home is all the way to the right. I powered up and armed at waypoint 1. All that was on my tablet were the 8 waypoints.

There was wifi being broadcast all over the island. Any chance the wifi overwhelmed my transmitter and killed the mission? Any help would be appreciated. Not sure if this was a fluke occurrence or if there is a problem with my hex. The damage was minimal although we almost lost the thing in the vegetation. Luckily the hex was still powered and we could use the telemetry signal to find it.

The beeps are ac3.3 acknowledging the change of flight mode, first beep for loiter second for stabilise.

It looks like for some reason ac3.3 changed out of auto into loiter and then into stabilise while your throttle was at 0%. This cut the throttle and dropped the UAV like a stone.
Channel 3 and 1 do some interesting things when it goes to loiter too, going from mid stick to full deflection and 0 throttle to 50% before reverting back when stabilise is selected.

Did you have the radio transmitter switched on for the flight? throttle at 50%?

The transmitter was on. I used to keep the throttle at 50% when I initiated the auto missions from the TX. But since Tower was updated to allow arming and mission start, I have the TX on in stabilize mode but throttle at zero just in case I need to take over. So what the heck could cause the mode change? Should I be flying auto missions with the TX off to avoid any pixhawk confusion?