Cannot start dated rituals

[ZahlGraf]

Hello

I have an issue with the Idiology DLC. I have two dated rituals (symbol burning and latern festival) and i failed to start both on the day where they occur.
Some days before I get the notification "ritual opportunity". Then wen the day comes, the hours are counted down in the description of the ritual. But when the counter reaches 0, it directly jumps to 60 days and I still cannot start the ritual.

Looking at reddit, it seems, that many other people had the same issue, without knowing the reason or a workaround to fix this.

Is this a known bug?