Y6B Flip and crash in PosHold

Firstly, I love the new 3.2 code, it works great on my quad.
My Y6B just flipped mid flight in PosHold and crashed breaking two props and a GPS mast, no major damage.
I can’t see the reason but it appears that the front left arm just went up in power and flipped over the frame. Looking at the logs I think that maybe there was a glitch in GPS Alt before it went wrong but I am not sure, the HDOP etc looks good.
No motor failure or ESC issues I can see and the motors were recalibrated.
I have had issues with throttle response, First time arming all good, second time arming (without repowereing) throttle jumps from 0 to about 30% but once throttle input is raised above 30% the response is normal.
Any ideas what might have caused thus crash?
Thanks you.

I had a quick look at your logs to see if it could assist me with a similar problem i am having.
I see a EKF-CHECK-1 AND FAILSAFE-EKF error, how is you compas mounted and did you calibrate after upgrading to 3.2?

This is the link to the ekf failsafe so you can learn more.