And once they start they don't stop again, which is also kinda annoying. I wish there was some way to permanently allow it, and not be bugged by the alerts again. Something the app cannot set by itself, but i can set.

I have some apps, i.e. Unifi Protect, that requires access to background location to send activity alerts when nobody is home, and i frequently get alerts that this app has used my location in the background, and despite selecting "allow always" it will pop up again in a couple of weeks.

To further add insult to injury, i appear to have "trained" my wife so well that she defaults to selecting "deny" for apps she doesn't use, and "only when in use" to everything else, which then results in a flurry of motion alerts :)

I have a feeling that's a bug. I have an app that I want to have background location and was asked twice soon after upgrading to iOS 13, then iOS was silent for about a month, then started popping up a prompt for it 2 or 3 times a day for half a week. After restarting it stopped popping up again, so it seems likely that something was broken about saving whether it had prompted for that app.

You get the popups until you accidentally block the app. Since the probability for blocking accidentally is greater than zero, over time all such apps get blocked.

This might hurt for example Tile. I think their “network effect” is somewhat depending on this kind of background location tracking.