Appeals Committee. Disputed situations in tournaments.

If such an episode happened in "Heroes of Might and Magic," I would recommend loading the autosave from turn 123 and continuing from there.

But since the players mutually agreed to change the rules of the game, they are responsible for the consequences.

P.S. Reaching turn 123 in Heroes of Might and Magic is quite a feat.

P.P.S. From a technical implementation perspective, I think it would be better to show the blue player the red player's turn after synchronization and offer to stop the "Heroes of Might and Magic" with a replay of the last turn.

After the red player has already made their move on turn 124? So, you are suggesting rolling back not just one, but two turns?
What is this fashionable nonsense about replaying turns? The player gains an unfair advantage because they already know what and where everything is, who is guarding what, and their sizes, and will be able to make moves with this unfair information.
Let's also give autosaves when players lose or misclick in tournament matches. For me, this is a sign of equivalence.
In my opinion, it would be much simpler to legally define "Heroes of Might and Magic" up to turn 116 (the time for restarts on the middle roads) and be done with it. Or, we can just wait for a patch sometime.