Ugh...so many sketchy things going on with this game right now. Beware completing Solo MUT challenges. I just played the one against Buffalo (2nd game of the "Prospect" tree), scored a TD to take the lead, then grabbed a pick 6 as time was expiring.
I finish the game, it shows the coin and pack reward...then takes me back to the menu and shows the challenge as not being completed, my coin total is the same, and the next challenge isn't unlocked. Fix your shit, EA.