Ideas and suggestions.

In Heroes, players take turns, and this order cannot be disrupted. Otherwise, how do you switch from Overlapping Turns (OT) to the regular game mode, and how do you end the game? How do you resolve conflicts? For example, both players capture the same neutral castle in one turn. Do you roll back both players' turns, and then what? Do they both capture the same castle again? Or should someone graciously yield? Are you, Dau, suggesting that we juggle the turn order?
Therefore, when a conflict (or contact) occurs, the blue player's turn is rolled back (that turn, which technically doesn't exist yet), and the red player continues to play as they were. Because the red player would have played the same way even without OT.