I recently ran into a DWG file that I couldn’t do anything with in the CAD View, in the Drawing View or even in AutoDesk’s DWG TrueView 2019. I don’t know the source of that file but I couldn’t even convert it to a different format in DWG TrueView. I ended up opening the file in the CAD View and choosing File | Save CAD File as and saved it as a DXF file. Once I did that, I was able to work with it in all three places with no trouble. Civil3D and possibly some other programs are creating DWG files that even AutoDesk’s products are not compatible with. Please let me know if this work-around helps and if it doesn’t, please email all of the file to me so I can take a look.