I can only go by my own experience. I bought some opened-box Kodak Endura paper off of ebay, and simply could not get a properly balanced print from it; there appeared to be very noticible crossover. The base had yellowed, but no evidence of light fogging. The paper had no expiration date. I bought some new and the problem went away. I vowed to always buy new, unexpired paper from a reputable seller.
I bought several boxes of Endura paper at the time Kodak discontinued making it in sheet form and there is some yellowing of the base on all of it, even thought it has been frozen, but no visible crossover yet, although highlights are noticibly off-color when compared to Fuji CA II of the same age which has a much whiter base. It doesn't bother me one wit that Kodak no longer sells it in cut sheets; there is Fuji to buy and I prefer it.
My ebay paper likely hadn't been kept cold and there is no telling about the OP's.
My problem wasn't as bad as the OP's, though, and likely a filtration or fogging problem is the primary cause.