Hi adonijah,
Thank you for using the Support Forum. Please take a look at the solutions for blotchy print. Also make sure you have done the cleaning detailed in the solutions for residual image or ghosting. If this does not fix the issue please consider contacting your support centre for further assistance.
This double print smear thing just started happening on my WorkCentre 6605DN today. I was printing a 154 page PDF on A5 paper with auto duplex. What's weird is it only did this on 24 out of the 77 sheets of paper. So, it's not a constant thing. Could it be the imaging unit or something on a drum? Printer only has a little over 10K prints as of right now. Is there a way to clean it?
I am working on a Surface Pro 3 with Windows 10, if it matters. I did have some driver issues installing on this new computer this past week, but I worked it out using the Win 7 drivers.