Why do notifications of places come, even if a person does not leave the place

If the geolocation in your phone is off or the signal is too weak, the phone can not receive the satellite signal and switches to the coordinates of the nearest cellular towers. In this case, “No GPS” sign appears next to the user’s avatar on the map.
The accuracy of the coordinates is reduced, so your location is displayed on the map beyond the radius of the place. And you will receive a notification of the place, even if you did not leave it.
When the signal of the satellite is restored, the coordinates will be updated and become accurate. The coordinates will move back to the radius of the place, and you will receive a notification again.

To prevent false notifications frequently, use WiFi in the room/transport for accuracy (usually GPS doesn’t work indoors).

Also, when you choose the radius of a place, do not forget that the accuracy of the coordinates is not stable. When an accuracy is low, a “jump” of the coordinate for the radius of the place can occur. Selecting a small radius of geo-location will increase the number of false notifications.