Restart did not resolve my problem.
iOS MAP and Google Maps do not properly show GPS position and tracking.
Starting a trip from place a to B in Toronto.
Open Maps, select destination, push directions button, select GO. This behaves as it should.
However once Go is selected and the MAP orients to show the start of trip, the arrow does not move as car moves, but tends to jump periodically to updated positions on the route. The map does not orient properly when turning corners.
THEN
everything seems to work ok.
The duration from start to when it appears to work is up to 10 minutes.
This same problem occurs also on Google Maps and on another iPhone 6s simultaneously although the final proper tracking happens at different times.
I no longer participate in thee AppleSeed program. My build is:11.2.6
There are numerous cases of similar issues reported in Google Search and the iPhone community