EKF Failsafe mystery

I was flying above the field where i usually fly, and suddenly EKF failsafe was triggered. unfortunatelly i am unable to find in my logs specific parameter which trigered this failsafe. Is anyone able to help me? (happened also in flight right after this one). What is wrong?2019-08-08 15-24-14.bin (2.7 MB)
2019-08-08 15-24-14.bin (2.7 MB)

Hello, recently I’ve got the same thing, but, as I’m using internal and external (from here2) comprass, perhaps im not going to have any problem.

What I’ve figure out is: when the drone went more that 500m from mavlink, EKF compass was triggered, only when drone was far from home, but, the mission didnt stop and I’ve got no problems.

Maybe is becouse i’m using rfd900 and as far it got from home, more power signal the telemetry will emit and perhaps this was the main issue.

I’ve followed some tutorial on internet and put some alluminum foil on bottom of gps and hardly ever EKF failsafe is triggered.