Having a similar problem. After speaking with Maia during The Courier's Calling when she returns from her mission, I am stuck with not being able to recruit those that were in my party prior to the event. Something about how it adds her back to the party. Added a save from 4 hours before at queens berth, the last save before I got the issue, and a save after just getting it (the autosave in the sea). Also went to the wild mare to experiment with party changing, and it got quite glitchy.
Dropbox link: https://www.dropbox.com/sh/45kuacl2z82pllb/AAD7M3aYfiRImHK9szzAcwu_a?dl=0
Cheers for your hard work!
Edit: actually the one at Queen's berth was hella messed up too. Added one before that, Engwithan Waystation save, where everything seems fine.