Playing on xbox series X, me and a friend have noticed an issue with XP gain over the past couple days. It used to be the case that we would get XP for kills throughout the mission, then the mission reward xp would get added on to our total. Now our XP bar after a mission doesn't even reflect the full amount of mission reward xp, let alone whatever kills we get in the mission. 

Example - I start a mission and my bar is at 75k. I kill everything and the mission reward says 84k. I look at my bar and it's only gone from 75k to 126k.

Is anyone else getting this or can anyone explain what I'm missing and why this is normal? It's like I'm being taxed on my xp.