I'm not sure if this will resolve the mystery, but, I saw the same thing appear recently when opening a .dwg file, which I had exported from Rhino 3D, as it gave me better profiles to work with, than importing the native .3dm Rhino 3D format into TurboCAD.
You can design without engineering, but you cannot engineer without design.
Using Win 10 with Designer 2016/2017 and TurboCAD Pro. Plat. 2018/2019 + Lightworks (64-bit versions) + AnimationLab 5.2.
Windows 10 Pro 1903 (Build 18362.418) 64-bit