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).
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Confirmed for 19w11a and 19w11b. The villagers have a very hard time getting to their workstations because of this.
Confirmed for 19w14b

Duplicate of MC-142817.