It looks like I am not getting the bonus XP from completing challenges related to Mirrorwatch. I haven’t gotten the bonus XP from any of the challenges I have completed as of right now.
I’ve noticed recently that when you get enough xp to complete more than one BP tier, the little progress bar you see at the end of a match will only show the XP gained from the match itself, but looking at the actual BP you’ll see the tiers be completed. Don’t suppose that’s what’s happening to you?
Also unsure if that itself is or isn’t a bug
Checked in this morning and had a few ranks of the battle pass that weren’t unlocked last night, so I think it may have been fixed. 
Have the same issue. I completed the 32 mirror games. It shows 5000k Exp in the endscreen but only 1884 exp on the bottom of the exp bar.