When host leaves game during mission loading, client looses most level progression and all currency progression.
On loading chapter 5 host decided to leave. Client had almost reached level 4. After connection loss progress was reset to level 2 with 0 renown currency.
It would be nice if the client saved network progress more regularly, because it is soul crushing to have progress reset every time a game is aborted, to a point where it almost becomes a blocker. I would rate this a critical bug for player experience.