There seems to be a bug with EVENT_QUEST_COMPLETE where it would fire twice when handing in a quest and the second time it passes wrong values (e.g. Champion Points = 16) which causes the bar to count up until it reaches my actual champion point count. For my 501+ CP this takes quite a while and it seems to prevent any further center screen messages from showing up until then.
I included a simple fix in the new version of
Medic.