I was literally watching as I was doing raid runs on Paladin at level 50. At first, I was under the impression that once you hit level 50, you just stopped getting EXP. However, as I kept clearing missions, my "rested EXP" bar kept getting bigger and bigger. I wasn't in a sanctuary. I never set foot in one. I just pushed through Castrum Meridianum and The Praetorium. I WATCHED this bar get bigger and bigger until it finally filled up and turned blue.

Clearly, that implies that the thousands and thousands of EXP from those runs were going somewhere.