I am level 50 and have had my experience bars totally filled for weeks now, and my screen since then still shows I gain exp when we kill a blue or higher. And there is no change of color, all the bars look like they do at any other level. Although I haven't died since I totally filled all my bars at level 50, I know others who have and if they continued to gain experience after filling them, they said they did not notice any loss of exp until they died several times. So don't ask me WHERE the exp is going, but apparently it is increasing past that 5th bar since you can die and not see any exp loss.

Mik