Almost a month without any return or consideration??? [:(]
I think, I found the process to reproduce the bug.
Step 1: creation of walls and rooms on 3 levels.
Removal of the ground floor room.
Addition of a French window (left side).
Addition of the room with recalculation and walls AND........... BOOM!
It is the bug of the piece of wall which returns.
The file is : HERE
[;)]
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