I am narrowing this issue down to a linked topo cad file. My trouble shooting process was as follows:
I have found that if I duplicated my proposed floor plan (which is correctly showing no transparency as expected) and then change the view template to my existing floor plan template (my existing floor plan is the one with the transparency issue) the transparency is gone and the display is correct. In other words duplicating the good floor plan apparently fixed the issue.
However if I un-check Crop View from any of my floor plans, regardless of view template, the transparency issue reappears. The crop view toggle turns this transparency issue on and off.
Finally, if I go to Manage Links and remove the topo CAD file from the project the issue seems completely resolved in all views and view templates, cropped or un-cropped. As a further test, with the apparently problematic topo removed, I linked another topo file from the same surveyor. No issue with this topo from another project. I tried auditing and purging the problematic CAD topo file and the issue persists. However when I cut/paste the problematic topo linework and other graphic elements into the good topo file I have from another project and insert that topo, the issue is resolved. There must be something corrupt in the topo cad file and I'll have to ask the surveyor to fix it. I can't just use the topo I fixed because the coordinates, etc. are for the other project.
So, I think I resolved this and am sharing all of the above as a lesson in trouble-shooting. I hope this helps others and may lead to an explanation or better fix from Autodesk.
Again, thank you to all contributors on this forum and this post thread.