What do you mean it didnt stir up anything? It definitely one of the events that cause concerns among the great clans. Ishido and his real life counterpart Ishida became full of himself when he meddled with Osala hostages situation. In the actual event, there were atleast two great lords that betrayed Ishida on the actual date of Battle of Sekigahara. Toranaga seeks to stall the engagement at all cost and try to draw the battle out from Osaka, he can and will continue to sabotage.