I set up three refining sessions all at once at one station then travelled away. I got 3 new mail messages saying all 3 sessions had completed.
Then I tried to start a new session at a different refinery but the game wouldn’t allow it as it “thinks” I still have 3 sessions (my max) in progress.
So it seems that until you physically collect the results from your refining sessions, those sessions are still considered “In Progress.”
IMO, it would make more sense that once these sessions are complete, you could start new sessions at any refinery and just collect completed refined ore when it was convenient.
What does everyone think?