I've unchecked the raid unit frames and party unit frames and refreshed. It still appears and wont go away unless I disable all unit frames then re-enable Unit Frames.

I support, the same trouble
only /reload ui is helping

I have the same problem.
I disabled the raid submodule of SpartanUI (SpartanUI_Raidframes in Wow Addon list), that made the problem go away.
I use Vuhdo for raid frames anyway.

I also disabled group and raid in modifications

Disabling raid submodule did not really help.

Every time someone is added to the raid or is logging in (and sometimes also when I log in after a disconnect) I have some visible unit frames of some raid members, even if raid is checked off and the raid submodule is deactivated.