I hope to get answer to what I think is a similar problem. When setting up walls in various layouts, one line of the wall is dark, the other light. I can't seem to change this, no matter what model view option I select or modify.
See attached screen shot...
Dave Olufs
Just 4 Measure, Ltd
iMac Pro 3.2GHz Quad, 32GB, OSX 10.13.6, AC-5, 6, 6.5, 7, stopped for a few years--started again with 12 thru 17, 18 or 19 didn't work, then 20, 21, now skipped to 23. Started in 1976 hand-drafting ink on mylar...