When you use your phone’s GPS system, it uses satellites to determine where you are. This information is then sent back to the device and stored in its memory. When you open the app again, it can access this data and tell you where you were at that time. However, if you have turned off location services, the app won’t know where you are.
Tinder thinks you are in a different city because it is unable to update your current location. This is what happens if you have your phone set to use GPS instead of WiFi. You can’t get any data from the internet until you are connected to WiFi. The solution to this problem is to turn off your GPS.
Keep in mind you may need to restart your device after doing this.
Finally, it’s also true that if your network connection is unstable, it could cause your phone to think that you’re somewhere else.