Ghost of Yōtei - Prediction of Caravan Path *DLC Spoiler*

In a previous update, I was able to maneuver my way into Clan Saito's Training Fortress(completed mission prior, but there were Saito Outlaws and Ainu in the fortress for some reason lol.). In the very back of the fortress, there was an open gate leading to a bridge. The game would respawn me each time I tried entering that gate so thought it was something tied with the upcoming DLC. After completing the DLC, I ventured around to make sure I discovered everything and at Toshibetsu Falls, I could see the caravan path in the final mission "Dream's End." I checked the map and it potentially looks like the path would have lead to Clan Saito's Training Fortress...to the gate I tried passing. I am no longer able to access the fortress. What do you think?