The code for spawning iron golems in villages is currently unstable.

If you are trying to build an iron farm, or if your old farm which used to work fine has stopped spawning golems, the issue might simply be the game itself.

For this farm design which I’ve made available for download alongside the demonstration video, I paid close attention to the details:

• I covered a 20x17x20 area, with bed arrangements of 4x3x4 and 6x2x4, respecting the maximum 6-block vertical detection range (both up and down).

• The entire surrounding area consists of either air blocks or blocks where golems cannot spawn.

• All villagers were individually linked to their respective workstations and isolated to prevent issues caused by them unlinking and relinking to the stations.

As you can clearly see in the video, the spawn rate can suddenly break. In the worst cases I've encountered, golems only start appearing again after an in-game day has passed.

EDIT: I mismentioned the bed dimensions in the files; they are 4x3x4 and 6x2x4 respectively.