Yes it seems to take the name colour from your top forum tag. When you get donator, it puts the donator tag at the top (above support) and therefore overrides the name colour.
From this, it also removes you from the staff page because this is automated. The workaround would presumably to make it so that donator has lower priority than staff positions in terms of the ordering.
The way the donation and tag system works is you have your primary group (like my development tag) and then additional ones, the donator rank is always set as your primary tag unless changed by management.
The issue with this is that considering it always must be your primary unless changed, then it will replace anything else which is there and therefore causes your other primary group to disappear.
Only fix I can think of is making it so groups cannot be removed but are just moved to the other groups slots to avoid this issue. As at the moment, it seems like it's just showing the one that was added to the primary slot most recently (explaining why your support tag came back).
@Neois your man for this. EDIT: *Wilco and Ciaran are your men for this* ?