Iron golems cannot be crafted occasionally in singleplayer. Have not tested for the bug in multiplayer. I have tried saving and exiting the game, then re-opening the world. I have also tried re-launching the game. Sometimes this can fix the glitch temporarily, but it typically doesn't. I have not tried uninstalling and re-installing the launcher.

What I expected was when an iron block was placed with a row of three iron blocks placed on top of the single iron block and a pumpkin placed on top of the row of iron blocks that it would create an iron golem.

What actually happened was that a majority of the time the recipe would not create an iron golem and the blocks would just sit there.

To reproduce this glitch, simply follow the recipe to make an iron golem:

1.) place an iron block on the ground

2.) place three iron blocks in a row lying across the first iron block placed. The middle iron block in the row placed should be directly above the iron block on the bottom.

3.) Place a pumpkin on the iron block in the middle of the row. What should happen is that an iron golem should be generated. However, due to the glitch, it likely will not work.