I read that villagers are supposed to only claim job blocks they can pathfind to. However, in our Realms village, villagers seem to claim any block within their range even if it's obstructed. 

We rebuilt a village and everyone got mixed jobs. We tried blocking them with blocks inside their houses so they will claim the job we're providing them. However, they will just randomly select a block within their village even if they cannot go to it. They also claim blocks inside our house that uses iron doors just to stop them from breaking in.