Hello Bruce,
After looking at your file, and doing some tests of our own, we could confirm all the things you said as bugs. We will try to fix them as soon as we can.
The main problem was caused by a complex profile that was not centered on it's origin, but had an offset to it. This caused various problems in the corners in floor plan (the profile was mirrored in the corners, and in some cases because of this, it couldn't even be generated in 3D). A workaround for this issue might be making the profile centered, and set an offset for the whole handrail instead. Of course this can't be done with a toprail, but you can just get rid of the toprail, and place a handrail on top instead.
I hope you will be able to get along with this suggestion until we can fix the problem.
Kind Regards,
Daniel Alexander Kovacs
Professional Services Consultant
GRAPHISOFT
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