Do you mean that when you run Google Maps in the background and then run your App Inventor app, the App Inventor app provides more precision than if Google Map is not running.
I expect when you run Google Map you see the gps icon and when you run your app (which you have not shared) it is running as a fused Provider. Running Google Map probably forces your device gps to use the gps Provider.
Have you tried ' to LockProvider to gps and set TImeInterval at something other than the default setting which is 60000 ms (one minute) while using the MIT LocationSensor.' to improve the precision of App Inventor.
??? I don't know exactly why. My previous comments describe a very good guess as to why. You realize, you have never provided an example comparing the 'difference' or showing your AI code You can improve the LocationSensor precision by working with the Provider setting.
Perhaps this could help GPS with Android 12