When you made the change to add BCC support, you changed the Focus frame event registration as follows:

ZPerl_Target.lua:

                if not IsVanillaClassic then
                        self:RegisterEvent("PLAYER_FOCUS_CHANGED")
                end

However you neglected to make the same change for Focus's Target, it still shows:

ZPerl_TargetTarget.lua:

                if not IsClassic then
                        self:RegisterEvent("PLAYER_FOCUS_CHANGED")
                end

You should using the same condition for focus target as for focus to register the frame event handling.

Fixed