At the release of 1.14, Many people on my server built gossip-based iron farms. However, Mojang changed Iron farms to be based on "panic" in 1.14.3, breaking all of our iron farms. So when we looked online for panic based farms and rebuilt our farms, we noticed that they still weren't spawning any iron golems. I decided to test the farms in a vanilla single player world because clearly they were working in the videos, and got good results; Iron Golems spawned. We don't have any plugins installed that should affect the way iron golems spawned, so we believe it is the result of a bug in Spigot 1.14.3.