This is a terrible bug that I think I have fixed in the next engine - just so you all know, it's come up I think 3 times in the various leagues here, and I have a server that is running a full season every day and it has taken me forever to track this bug down because it only happens once every 5-6 seasons. But I believe it's been fixed in the 0.2.1 engine.
I would love to have an equitable way to fix this game - right now though I don't know of one. There is always the probability that he could have fumbled and the FG attempt never happen, or that the FG could have been missed, or even that the ensuing kickoff could have been returned for a TD or at least into FG range for the win the other way. The other thing to think about is the games that are lost because of a terrible call - i.e. that pass interference penalty with the Packers and Seahawks back in 2012 - where once the game is played any mistakes by the refs, even if it can be proven would have changed the outcome of the game, don't do so. The only way I can think to fix it equitably would be to roll back the league to re-sim the entire week, but that wouldn't be fair to the other 30 teams not affected by this game.
Believe me, I'm as unhappy with this as any of you - I just don't see a good way to fix it for this game.