Go to the compass itself and use it a few times. Might just help. I use the Huawei p smart 2018 and it works fine.
I tried this several times to be sure it's working, no change. Also I checked all the permission for FPV app and compass in advanced settings, all enabled. I have disabled few useless google built-in apps, only difference between factory settings. Maybe would be helpfull to know which permitions VGPS requires.