Villagers, wandering traders, illagers and other NPCs often get stuck between blocks and fences.

This happens typically in savanna villages where some house have fences placed diagonally, therefore not attaching to the block.

It will make some weird situations happen, like an illager not chasing a villager that's standing literally three blocks away from him (see screenshot).

They can eventually get themselves free (when they update their pathfinding I guess).