I have been having the same issue as a few others that posted with the GPS not tracking properly and “bouncing” around seemingly at random. After trying all of the suggested fixes (rebooting phone, restarting GPS, reinstalling game) I had no luck. I then messed with the GPS settings and set it to phone only and suddenly its tracking properly. I am on an S8+, instructions to do that are: settings > connections > location > locating method - select phone only.
My phone was previously set to High accuracy and I noticed that when it jumped around it would show me as being at the location of the router or other wireless signals around, before it would jump to the next one. I have had no issues today using “Phone only location tracking”. Hopefully switching that will work for some users as well as it has worked for me!