CAD PDFs imported to Illustrator change lines and are not true to drawing

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I've been having an issue importing pdfs from Autocad into Illustrator.  In my Autocad file, all of my lines have 90 degree corners but in Illustrator they are skewed and do not have squared corners.  I checked the pdf to make sure the lines exported correctly and the issue is not apparent there.  This issue has been happening in all of my drawings and not just this one in particular.  The first screenshot is from Illustrator showing the corners that are meant to be 90 degrees.

My second issue is that curved lines are showing up jagged in Illustrator and not even close to how they are supposed to be.  The second screenshot is from Illustrator and shows what are meant to be rectangles with rounded corners.  

Any help would be much appreciated.  I've been dealing with these issues for a while but can't find a solution.  

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The lines are meant to be on a diagonal.  By skewed, I mean that the rectangle is meant to have all 90 degree corners but it is slightly off