Just got this today. Went in to Obol Crossing (Pluto Proxima) with a lvl 21 Mausolon and ended the mission with it at 27. No bonus affinity granted when moving to the Dojo dry dock, where it still showed 27.
Then I extracted to the Liset, and the completion screen showed bonus affinity granted up to max rank (30). When I went in the loadout, it was still 27. Rebooted the game, still 27.