I noticed the blue title bar today in my iPhone SE 2020. But when I look into the task list (doubleclick the home button), there is no navigation app running. I swiped up ever running app and the blue bar remains.
I suspect it is the OsmAndMaps app I installed recently. Oh wait, after I tried to make a phone call, the title bar changed to "OsmAnd Maps is Actively Using Your Location" for a few seconds.
So the question is now: how come it is using Location, but not listed in the task list?
Not that I use CarPlay and this happened after I left my car. I did not use Carplay there, but it might have done things in the background.