I got to the very end and spoke to Odo.
It looped back to the beginning of the "Sacrifice" section when you beam down to the Founder's home world.
New Vanguard Jem - first episode arc.
Anyone else have something similar? I am debating completing it again, because I want the Morphogenic set, but really don't want to be caught in a causality loop and keep reliving the final section of the episode.