I have an iPhone 6, Google Maps periodically would give me issues after an app update or an iOS update where I would have to delete it and re install it in order for it to function properly. It would usually have problems with triangulation of where I am on the map, actively tracking my movement, and failure to keep the compass straight (either the arrow or the map itself would spin wildly).
Sometime around June 2018 Google Maps, Waze and Apple Maps all started to exhibit this problem and deleting and reinstalling and/or rebooting didn’t solve it. Based on the suggestions found in this thread, I did the following and it eventually rectified the problems:
-Rebooted
-Deleted and reinstalled Google Maps
-Deleted and reinstalled the Compass app
-Re-calibrated the iPhone compass by going into privacy settings and turning on and off the location based compass setting switch
-Setting the compass options to “true north”
I may or may not have done those in that order, and I may have done some more than once but eventually, Google Maps started functioning properly again (and frankly better than it has in a few years I think, it seems to be much more snappy on turns and quicker to call out upcoming turns, etc.).
I hope this helps somebody else having this problem, as I didn’t really want to have to upgrade my phone to use Google Maps again, and I use it for EVERYTHING (best innovation of the past century)!!!
Good luck all!