Hello there, Thank you very much for reaching out to us. I'm sorry to hear that you are having trouble with the Solstice questline that appears to have gone missing. We've received some reports of this and are investigating the issue further. For the time being, this quest is not needed for any of the rewards. It is mainly there to guide you through what you need to do to unlock the armor pieces and imbue them. That said, you can still do all of these actions without the quest, and should be able to get the momento at the end regardless of quest completion/existence.