EKF position and velocity variation error

I’ve seen a flight today with an EKF velocity and horizontal variance error together with drone position sudden jumps (check attached figure what should be a straight take-off path), resulting in erratic navigation. I’ve experienced this type of problem when losing GNSS data, but in this case the receiver was working with 10 sats in good conditions. May this have been a GNSS glitch sporadic error or may it be related with something else?

I attach a link to the telemetry log (starts at 67%+), I’m sorry but I don’t have the binary log because the drone user doesn’t store them: https://www.dropbox.com/s/wcyqw2cpaecvezr/2020-09-04%2009-45-29.tlog?dl=0

Thanks in advance!