Faulty GPS

Hi.

I have some problems with GPS accuracy on my Enduro. It was set to GPS+GLONASS by default and after sw update it started misbehave. While running my cadence was constant (same song at 180 bpm) but my pace varied from 5:25 min/km to 7:10 min/km. I switched to GPS + Galileo and first couple of days everything was fine. Then the same thing started to happen. Power mode is set to normal. SW version is 16.70. Screenshot attached is from todays run (GPS +Galileo). Is there any way to fix this?