Villager tend to leave their village

Put the summary of the bug you're having here

What I expected to happen was...:
i thought i could enjoy returning to minecraft after many years?

What actually happened was...:

I am playing on a new world in single player but i noticed that all the vilager tend to leave the village and get stuck in ravin or in the river, and this result in the death of them.

I thought iwould fix itself eventualy so i went away to buuild my base but, sevral days later, the AI made them climb moutains and went way past ther village, and after saving them from a raid, only 2 of them survived.

i had 10 before, so plz fix their AI so we can play normaly

Steps to Reproduce:
no steps