It's currently glitched and doesn't give XP for the waves you completed, just did all 30 waves in stonewood with 2 friends and didn't get any XP afterwards, regular missions seem to be giving XP though.
Can confirm.
u/chryztos At 5pm EST I finished running Plankerton Endurance, all 30 waves. Did not get a single XP award for BR. (I had restarted my game after the XP change took affect in case someone thinks that could make a difference)
Hey thanks for the tag. Currently collecting reports and looking into it.