I could be wrong here, so take it with a grain of salt, but you did mention it's a hosted server. Do you happen to live with other players? I believe the game checks each players potential to trigger a raid separately, so you can end up with more raids or more frequent raids if multiple players are in the same place that meets the raid requirements (for everything but "you are being hunted" this is a base basically). Again, not sure if that's what's happening, just the first theory that came to mind as a possibility.