Labels were old and discolored

I order from Stickermule all the time and normally love their products. I recently ordered these square sheet labels and was really disappointed. The printing was fine, however, the actual labels were quite old and discolored - faint yellowish in color and some were difficult to remove. I'm wondering if the sheets I received were sitting on the shelf for a long time before being printed on? Hopefully this was just an isolated incident (again, I love Stickermule products.)