Villagers breed despite maxing out beds and join professions despite there being no reachable job site.

I've built an under ground base and cured two zombie villagers to form my own village under the ground. They populated my base pretty rapidly so I had to build a separate section for them behind iron doors so that they didn't flock around my furnaces and chests. They still breed beyond the number of beds available.

Are they blindly finding beds and job sites within a certain radius or are they making sure that they are reachable? It's physically impossible for them to reach my beds and benches since there are two iron doors and it's around 20 blocks away. How far away are they looking? Sometimes they have problems finding the second bed room that I've built for them as well so their behaviour seems unpredictable.