I had something (sort of) similar happen to me yesterday on my FM07 game, albeit my own fault in a way -
Near the end of the game, we're winning 1-0 (I'm Atletico Madrid) and my GK fouls outside the box resulting in a straight red. I take off Aguero for a new 'keeper and play as a 4-4-1 Defensive, thinking I'll hold out to the end all being well.
Next thing I realize that my GK Leo Franco is bloody playing up front and Fernando Torres (ah, the joys of FM07!) is playing in nets, this is because I always have Torres and Aguero swapping positions throughout the match.
In blind panic I quickly try to sort out the situation and swap the players back. Just then the opposition win a corner.
It's at this point that GK Torres and ST Leo Franco decide to swap back to their proper positions.
As they are running up and down the pitch respectively, the AI can't believe their luck and quickly take the corner, scoring into an open net.
Cost me two priceless league points, that little moment of madness on my part.
What a wombat.