Hi Bob,
You can ignore the message. The fact that Google Maps do not provide ready event. That is, it's impossible to know the time when Google Maps are ready to go in runtime. Appery.io component module works so that on Page Show event all the components are updated. At the same time, this isn't incorrect or wrong behaviour for Google Maps component. Just this is the logic of work with this component.
On desktop browser tester, you won't be able to call a standard Geolocation service because of the dependence of the service on the device. That is, you can check it out on an actual device or emulator only, and for the installed binary executable APK/IPA only.