I have actually tried a new fresh install, and brand new mock-up drawings on Windows, Mac, and Linux, they all fail the same way.
Because the common thread is me, and something I could be doing "wrong", I am not prepared to say it is a bug yet.
I have in fact deleted the PCB many times, and dragged it over from parts appropriately and then the failure continues.
For this prototype, rounded corners won't kill me, but in the long run I need to be able to use rectangle.