Loss of control of x8 towards end of flight

Yesterday I was doing some manual flying with my x8, running Rc14 on a Pixhawk, in loiter mode, when the drone started to behave very strangely. It suddenly shot off away from me, and I could barely slow it down with the transmitter. I switched into stabilize mode, but still had little control, and it continued to behave strangely, including raising altitude significantly and drastic roll/pitch oscillations. The fact that it began to shoot off made me think of a GPS issue, but from the logs GPS coverage was solid. The auto-analysis revealed no problems with compass health either. I’ve looked at vibration levels, board voltage and such, but nothing seems terribly out of the ordinary. Could it be a power related issue? Or some kind of interference?

Something similar has happened before too. After an RTL portion of an auto mission, a different x8 of mine began flying around in a seemingly random fashion. I switched into loiter mode and it continued with this strange behavior, but then when I switched into stabilize I regained control and was able to land safely.

Any help shedding light on these issues and how I might be able to avoid them going forward would be much appreciated!

Logs are attached. Unfortunately I do not have a .bin file for the second mission I mentioned.

Vibrations are very bad. Did the board come loose?

I switched into Alt hold shortly after the strange behavior started happening, so it appears the vibrations only got bad after the drone started misbehaving.