AOA Issue Caused Unstable Flight- Help!

Hello,

Yesterday, I flew two flights with my VTOL plane. Arduplane 4.3.3, Cube Orange. The first flight looked absolutely fine. The second flight was disastrous. Pitch and airspeed were all over the place, the aircraft was barely controllable. I’ve studied the logs and found that for the second flight, AOA was completely off. During the first flight, AOA and pitch were more or less the same except for during climb and descent. See below for relevant graphs. My current suspicion is that it’s a problem with my cube, but I’m not sure. How is AOA calculated? Is there any other data or parameters I should examine?

Altitude, pitch, AOA:

Altitude, pitch, desired pitch:

Altitude, AOA, airspeed: