Despite the villager (pictured in attachments) being unable to claim the workstations (pictured) because there is a block above them, it attempts to pathfind to it, leading to him getting stuck until the work part of the day is over.

It seems the villager always pathfinds towards the highest available block that's above the workstation and on its x-z position. After reaching this point, it stops moving and stares downward.

After removing the workstation or the block above it, the villager pathfinds normally again and doesn't get stuck.

Likely related to MC-193105, but that issue only touched on armorers. This affects all types of workstation/villager. I do not recall this behavior being intended, and it is not resolved as of 1.16.3.