Football manager 15 online multiplier problems

Started a 3 player online game a couple of days ago with friends and we managed to get into the premier league season (It took a while). First game of the season pitted 2 of us against each other but when we got into the game none of us could make substitutions or anything, the assistant was in charge of the game for both teams. This happened in the next game and then in a third game it was all working fine but then at the 50 minute mark the assistant took over again.

Does anybody know why this happens or how to fix it?
Thanks