At this point, there are basically two separate reports of GPS issues in Google Maps, and while they may seem related, they can be resolved in different ways.
First of all, there are users who claim that the GPS signal is lost when the phone enters a locked state (when the device locks and the screen turns off). This happens on a variety of devices, including Google’s very own Pixel, and it’s pretty much caused by the battery management systems on these devices.
In other words, the GPS connection is lost because Google Maps is not allowed to run in the background in an attempt to preserve battery life, so what you need to do is whitelist the app and set an exception in the battery management feature.
Second of all, the GPS problems also occur with a slightly different behavior on Android devices, with some users revealing that the app just doesn’t update their location. This means that despite them moving, their location isn’t changed, with Google Maps thinking they’re still standing still.
This also appears to be happening on iPhones, so it’s not an issue that’s just limited to Android. And right now, no workaround seems to exist, as users who took to Google’s forums claim they’ve tried everything from clearing the cache on Android devices to reinstalling the app on Apple smartphones.
It remains to be seen if and when a fix for these problems could land, but for the time being, using Google Maps doesn’t make much sense since the lack of GPS kind of defeats its purpose.