The title says it. A boss debuff, which is - for instance - a magical debuff and can be dispelled as a magic debuff does not get shown as a magical debuff on the group or raid frames (with or without addons).
For instance at third boss in Halls of Atonement the magic debuff, the boss gives two players regularly, only gets shown as a boss debuff but not as a regular magic debuff (in addition). So you have to guess and/or remember, which boss debuffs are dispellable. I like to color my unit frames with the corresponding color for dispellable debuffs - blue for magic for instance. This does not work with boss debuffs atm.
Same with the debuff from Soul Hunters in Manaforge Omega.
Tested with standard UI, Danders Frames and Grid2.
Change that pls.