In my limited understanding, there are two mechanisms by which your location is identified, when on WiFi.
Firstly, a guess might be made based on the IP address assigned to your broadband connection. These guesses are usually wildly innacurate
Alternatively, the MAC address of your AP, as sent in WiFi traffic, may have been recorded in a database. Such databases depend upon crowd-sourced data from devices (smartphones) within WiFi earshot of your AP. Such devices know location from GPS, so can “phone home” and add your AP’s location.
So, on the first point... does your ISP allocate fixed or dynamic addresses and if the latter, any chance it got assigned a different address about the time things changed?
On the second, have you changed any hardware items recently?