I just got to this part of the story this morning after maintenance. Torian joined the team, Mako showed him around, then I had a convo with him before I hopped off the ship at Quesh. I intended to summon him as my companion for Quesh, but when I hit N, he wasn't in the list. Confused, I got back on the ship, and now he's not on the ship either.
So not only did the maintenance not bring him back for people who already lost him, but the bug that makes him go missing in the first place seems to still be very much alive.