Bug SetDestination returns false with no feedback

My npcs are trying to reach something that they absolutely should be able to, they walked a long road to get to where they are stuck right now, so there is something specifically about just this very small path that they seem to not be able to get to. Please pay attention that they had been walking normally until they reach this spot, so none of the "set to default humanoid" or other copy paste solutions apply.

NavMeshAgent.SetDestination

simply returns false every frame, for all of these characters, but still works just fine for all others. The only thing in common is that they are all trying to reach here. This happens both in Editor and in Build (screenshot).


There is nothing wrong with the navmesh, and those crop plots do not have collision.
What do I do? I have no access to source and there is no documentation explaining on why it could ever possibly fail to request a path.