I think Osiris used the Infinite Forest to see Rasputin’s actions during the time of the collapse and isn’t happy with it nor does he fully understand the choice. I’m not expecting anything monumental story wise such as an evil Rasputin or changing alliances because this is Seasonal content and not a static DLC. Since Rasputin is a static DLC his character will resume the same role he had previous to the season: mysterious but a non-combatant.