Device Encryption - difference between "Not encrypted" and "Unmanaged"?

I wonder what the Status in the Encryption dashboard means:

under which circumstances is it showing "Not encrypted" and not encrypted & "Unmanaged"?

On the screenshot all have the encryption module installed, except one computer.

The filter is "Computers that are not encrypted".

Edited tags
[edited by: Gladys at 3:03 PM (GMT -7) on 3 Jul 2023]