Villagers cannot pathfind properly along the y-axis and are often confused by major terrain variations they should be able to navigate, as well as when in a multi-storey building.

I have a two-storey apartment complex for the villagers in one of my worlds. The villagers will often get stuck in a room on the second floor if their destination requires them to backtrack along the x or z axis to get to the stairs. I've observed the opposite occur as well where villagers bumble around on the first floor trying to reach something on the second. They do get it sometimes, but often because they wandered in the right direction.

To replicate this glitch, you must simply create a multi-storey building, put some beds on the upper floors, and then put jobsites on the first floor and outside on the ground level. It helps if the destination is very close to the villager along horizontal axis, but is just too far along the y-axis.

Something similar can happen along the horizontal axis if the villager's path is obstructed by water/lava/chasm, and sometimes even a building. Even if a route exists naturally, if the route is maybe a little too far away, the villager won't use it. Although it will then proceed to wander around for a bit, it usually doesn't wander far enough to see the correct path, so when it spontaneously decides to head toward its jobsite again it still can't reach.

I know the mechanics currently work using a radius, but I think iron golems and villagers should be able to pathfind throughout the entire village area, considering it's their home.