Just ran into a known issue from the original release in Legendary Edition.
The "Rita's Sister" quest enters a bugged completion state if you talk Chellick into releasing Jenna immediately, agree to help him after, and then speak to Rita before completing Chellick's request for help.
If you do this, speaking to Rita completes the quest without getting the rewards from Chellick (including possibly 8 paragon points).
So, to repeat the repro steps:
1. Get the quest to the point where you must meet Chellick at c-sec
2. When speaking to chellick, charm or intimidate him to release Jenna
3. Agree to help Chellick with his investigation
4. Speak to Rita -> completes the quest. You can still speak to Jax, choosing to play along, or kill him.
5. Speaking to Chellick results in no conversation, and no rewards.
I believe at 4 you could instead complete the confrontation with jax, and then speak to rita. This should also break the quest, completing it before getting rewards from chellick.
This wouldn't be a huge deal if the quest didn't have such a large paragon/renegade reward.
I imagine the bug is simply that the completion condition is speaking to Rita if you refuse to help chellick, and this condition isn't blocked if you decide to help him instead.
