Though on the legendary edition it says: *first time purchase of this edition will grant you access to the season that is currently active when logging in for the first time after purchase. So depending on when you purchased the legendary edition it may factor in as to why you can’t access S13 exotic quest. (That’s just my guess)

Might want to get in contact with a mentor or contact CS whichever you prefer.

Does legendary edition say deluxe because my understanding is deluxe edition is only way to get previous seasons.