I was using onTap 8.3.2. If that is indeed the behavor then that would explain the lag in the volume deletes. Although, it doesn't explain why the old Qtree's were still behing displayed in OSM, but not the CLI.
But I think I have a work around. I ran through the entire transition again with my small 5GB volume. And when I was finished, and I strated clearing it off my cDOT system. This time Instead I deleted the Qtree's first, then the shares/exports, and last the volume. Deleting the volume last ensured there were no artifacts left in OSM. Also, this time when executing 'qtree show' and 'vol show' everything showed as being deleted.
I know there are dependencies in place to prevent a person from deleting a volume in OSM that has active shares/exports. But they should probably put one in place for Qtree's as well.