Honestly , I would return it.
The only way for it to skew is for the paper to feed crooked through the ADF, which is why the scan on the platten works fine
ADF scan, paper moves, light stays still
Platten scan, paper stays still , light moves
Cause of the paper moving crooked are multiple:
1. The paper gets picked up improperly by the feed roller.$69 gamble there, and on a new machine, probably simpler/cheaper to just trade it back to Xerox as defective
2. The Paper guides are not holding the paper properly
3. Thin paper that kind of folds up instead of laying flat while feeding so it goes in crooked.
But no matter the scenario, it has to be hardware based, because there certainly isn't a check box enabled/available that will skew a job through the ADF/DADF , and when a new machine has a hardware problem, I always advise its return, because you should not have to buy parts for a new device, and hardware problems always have a cost.