Location services failing intermittently

I am reposting this issue, in case anyone has any advice. My app uses location services (Google API) to determine if a user is at a particular address at a particular time. I have tested my app on several devices. Everything works as expected much of the time. However, from time to time, the location is not being correctly captured by the app, or the location is not properly refreshing. This error occurs both on a native iOS build and on a web app. I have not tested it thoroughly on Android. The key question is why location services might work properly much of the time, but then often fail. Please note that the issue is NOT with the location permissions. I query the user to ask for location permission in multiple places in the app. In addition, the fact that it works much of the time means that it is unlikely to be an issue with permissions.