There are some geo lookup tools here you can try running your head end IP address through that might help.
I tested Google maps at my home office and then connected to some different Meraki VPN's in different states and Google still knew I was at home. Presumably other data points like BSSID or who knows what else besides just the public ipv4 address I exit from?
But, to be clear, you are saying your devices without VPN works as expected and then when you connect to a Meraki using OS VPN client geolocation just doesn't work at all? Or?