Same problem here..
@ubi-smash After going back to the older save it restarted the Yule Festival and I have saved and restarted the game few times and the festival is still active on the older save but it's still gone on my main save. I'm on PC.
@ubi-raziel Loading an older save seems to work for me but i can't afford to lose 35h of gameplay
Same thing for me Yule festival is gone