Video of Farm: https://www.youtube.com/watch?v=3I2jsINPGro
World Download: https://mega.nz/file/pgpV3QbZ#shT6AOxha9ZKU3MlsMKIlcnNvQKgR65uwmBHb07Khcc
I've tested this farm with and without mods in survival and creative in Forge 1.14.4-28.2.0, 1.15.2-31.2.0, and 1.15.2-31.2.22 as well as vanilla and with Optifine 1.14.4 HD U F5. In both vanilla and Optifine, the farm works as expected, golems spawn and walk off their platforms immediately. In all versions of Forge tested, with or without mods, golems on one side of the farm will not pathfind off the ledge, but the other side of the farm will. From here, I can only assume there's some problem with Forge's pathfinding that breaks this.