Can't redeem 99 Patrick Mahomes

Yep, I'm assuming you're on PC too? It's been an issue for months now, and they don't care about fixing it. If you've ever upgraded the 97 ovr Superbowl champion players before, even if you remove those upgrades, they can't be used in sets. It's the same for all the promos and sets, including the MCS Tariq Woolen set. You're best bet is to sell the Superbowl players you're trying to use in the set and buy new ones from the auction house, but don't upgrade the new cards before redeeming the set. It's kind of sad that the community has known about this issue for months, and we've even discovered the cause of the bug and everything, but EA just won't listen or fix it.