Thanks for the file which helped me to reproduce your issue.
The problem comes from the small walls you drew in some corners as shown in the following image:
As you can see, it creates some walls that may have a null length side, and a part of the program that measures the distance between an object and wall side failed for a side equal to zero.
I fixed this bug and the correction will be available in the next version.
Meanwhile, you should avoid these small walls and connect directly walls while drawing them.
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Emmanuel Puybaret, Sweet Home 3D creator
