Wicked Cultist Mob doesn't spawn

Bug Name:

Wicked Cultist Mob doesn't spawn​

Bug Description:

Wicked Cultist Mobs which should be appear on night time doesn´t spawn at all.
https://bddatabase.net/us/theme/4194/

Needed to get knoledge and for this quest.
Knowledge: https://bddatabase.net/us/item/34194/

Quest:https://bddatabase.net/us/quest/2001/37/​

How to reproduce/proof:

Accepted quest
Wait til night 10pm-7am
wicked cutlist does not spawn​

 

They do appear but they do not stay around for long (as far as I know) at around 10pm-11pm or so I found them the last time.