I hate these type of bugs, they sneak past me all the time.
Could you tell me what you did before going into the building? Or did you maybe start the game from an old save?
to tell the truth me too encountered that bug, I used the second save with the build, for what concern what I was doing... well, I was just roaming around for the scenes and this are all the duplications I found
for this one I just moved from first to second with the passage no teleport
for this couple the second wasn't present when I entered
contrary to the other this duplicate is solid and can't walk through
aside this duplications here another bug I encountered, during the fight with the orc outside the boss room I had sana like the first pict and the orc grab her but if the orc is killed they stuck together till the end of the fight
anyway, I tampered with the save using saveeditor and only added money and stats for sana and anon