Thanks for reaching out. If I get it correctly, you are opening DWG file in Illustrator and your artwork is not showing properly. I am not completely familiar with CAD files, however, I may take a look and share it with the Product team if required.
Please share a sample DWG file and video of the workflow if possible. This will help us understand the issue and assist you accordingly.
Or if you have autocad, you can simply start a new drawing, draw 2 shapes next to each other. In your layout tab, put two viewports next to each other. Each viewport shows 1 shape. Save your file as 2010 version (or anything below 2010). Open this DWG file in illustrator and select open layout1, then you will have this problem.