That's normal. It because Items Grades were changed for the DLC items addition to the system.
Example (say before patch White0-10/Green11-20/Blue21-30/Purple31-40/Orange41-50 then new items required more Purple or Orange. Which things changed something like this White0-11/Green12-19/Blue20-28/Purple29-39/Orange40-50) This probably the case but it not a bad thing however if items appears out of the grade range well we may see odd color items.
Just say one more quality improvement for them.