This interested me enough to convince me to click through to the article itself. Is your observation allayed by this rule?
> Rule 2: a. Moves are tried in both orders, and only moves that are legal in both orders are merged. b. If both moves are legal in both orders but a different game state is reached in each order, neither move is merged.
> Rule 2: a. Moves are tried in both orders, and only moves that are legal in both orders are merged. b. If both moves are legal in both orders but a different game state is reached in each order, neither move is merged.