This is an old post so I'm assuming you've already fixed this issue, but for anyone else who may be having this issue make sure you've beat the map on nightmare difficulty, if the problem is still occurring just re-run the map again. If the problem is still occurring then it's a bug in the game and report it to the devs, this is honestly the best advice I can give to this issue and I hope it helps at least a little to anyone who may have this issue