I first thought there are scaning_artifacts on the scan, but other scans taken at same time don't have them.
these might be printing issue.

I would tend to agree that its a print error, perhaps a defect on one of the drums. Its easy enough to fix, except that I can't as the fine detail on the dress is still beyond me.
A data error would cause errors to continue from the point of the error. I get it sometimes if I've had the laptop running for over 7 hours and I download a several Mb image.