Hey there, your Warlock attempted 'The Arrival' on Legendary in September 2022 then completed it on Normal instead, they have not reattempted a Legendary completion. Try finishing that mission on Warlock first and see if that prompts you to pick up the Legendary reward from Ikora. In addition, former 'lost sector' exotics are now just focused initially from Rahool from his 'novel decryption' page, there's no prerequisite, just a material cost. Make sure you're on the right tab, not the one where you can focus already-obtained exotics.