Hey there, to qualify for the campaign exotic, your Warlock needs to have played all 14 missions on Legendary. There is a bug where by completing 'The Invitation' on Legendary, it marks both itself and 'Commencement' off on the Legendary triumph. That can cause players to skip that latter mission on a Legendary replay, thinking it was not necessary or already done. However if you skip it, the character will not qualify for their exotic even if the triumph gets completed. Your Warlock needs to complete Commencement on Legendary and then should be able to pick up Eunoia from the Altar of Relativity on Kepler.