For the of parasite exotic quest step 2 has you complete the birthplace of the vile quest. I did this with one other person in my fire team who got the next step. I even heard the worm dialogue, however, it did not complete the step for me. I replayed the strike once waited a day and played it again solo. I even abandoned the quest and reacquired it and did the strike but it still made no progress. I have the triumph marked that I completed it the strike the first time but no quest progress. Thank you!