We've been having this same issue since around October. It was happening with new Android (Samsung) phones as well as ones that rebooted after a security update. All of the devices were registered under Device Administrator. I read someone else got it working by assigning Intune licenses. (We were using the free device management from Office365 for most users.)
As a test, I added a few MS365 licenses instead of Office365 (both E3) and sure enough, all of my non-compliant Samsung phones shows compliant. So there is definitely something up there. It's not affecting Google Pixel or Motorola phones. It's don't understand why licensing fixes it.
<opinion>
This is something the vendors need to work together on to create a fix for the existing platform without having to purchase additional licenses.
</opinion>