This was added after the first patch. I think it was intentional on the part of the devs. That area was likely to be a "one off" area where you can visit it only once and never return. Since they made it part of the main Minrathous map rather than its own little sub-map, they need to put a physical barrier there to stop people from returning.
seems like an oversight because there's a chest in that area that i don't think was available at the time, meaning it can never be available.
Yeah, if there's something you can only get at one specific point in the entire game during a specific encounter, it would be nice if the devs would have added some of that VO your party members do to clue you in (e.g., "we should look around"). Or maybe put up a barrier where you can't leave the area the normal way at first and are forced to try and go out the back way and clear it before you can leave out the front. It's very frustrating for this type of game to put in an area that can only be accessed once ever and not have any clues or guardrails to make sure you don't miss it. Us completionists are crying rn.
