It is not a surprise, it is already happening. You can turn it off, but AFAIK if you don't it collects this information even if the Google maps application is not open.

Google absolutely harvests phone GPS data to enhance things like AGPS (mapping of wifi MAC addresses, or celll towers to location coordinates), and it does this regardless of the location setting in the system UI.

https://www.theverge.com/2017/11/21/16684818/google-location...

I have to keep location services (android) disabled to keep my daily movement from appearing in google location history.

GPS is definitely the best way of ascertaining a device's location but far from the only one. Google's own location API lets you access fine location (GPS) or coarse (triangulating via cell towers). After public outcry and legal action Google stopped driveby data harvesting by Street View vehicles but it remains unclear if they stopped collecting SSIDs and MAC addresses (I guess if you squint hard enough you could say that these are publicly available data points).

It doesn't take too much tin foil to think that android may be phoning home when it detects an SSID, the physical location of which is already known.