Bug compass only works for phones with compasses
Not every phone is equipped with magnetometers. Lower end phones do not have them.
With scanner redacted, and pokemon Go, the compass arrow is oriented with regards to the map, and rotates with the map regardless of whether or not the phone can detect magnetic north.
On my phone that I use to play Ingress, on Ingress prime, the compass icon always points up, regardless of map orientation, despite the fact that the compass works fine in redacted and pokemon go. I've discussed this with a few fellow agents, and some of them experience a similar issue.
With prime, it appears that the compass only orients to the map on phones that ha e built in magnetometers.