@violine1101 This is not the problem: they don't find the way in general 🤔
The mobs should normaly walk through the way.
In this case its only confined with slabs, but there can be normal blocks as well.. You can look at the pics.
I guess there is an issue with the pathfinding in 1.13 in general..
Tried also zombie and villager: same problem
I attachted some pics
Hmm ok, i will try...
Thx🤗