I have an Edge 1030 connected to GCM on a Google Pixel 2, my wife has a Edge Explore 1000 connected to GCM on a Sony Xperia Z5. Lately, we have both experienced problems where when we open livetrack to see where the other is, all that we see is a blank blue screen. Zooming out sufficiently eventually shows that the map is positioned in the ocean somewhat south of the Bight of Benin, off the west coast of Africa at about latitude 0 longitude 0. The problem is *not* due to Livetrack starting before the unit gets a GPS lock - today my livetrack didn't start until I had been riding for almost an hour (livetrack autostart doing its usual flaky thing), but when I upload the activity to Garmin connect, I can see from the track that the GPS was working correctly from the start of the ride.
I note from browsing the forums here that we're far from being the only Garmin users seeing this problem...
