Minecraft Version: 1.16.5
Server Type: Forge
Forge Version: 36.0.46
Mod Version: 1.1
KubeJS Version: 1605.3.6-build.172

Every time an item is spawned in the world such as dropped by a player or dropped from a block that was mined this error is displayed in the server console:
[02:59:56] [Server thread/ERROR] [KubeJS Server/]: Error occurred while handling event 'entity.spawned': Wrapped java.lang.NullPointerException (server_scripts:unify.js#136)

Despite the error it still converts the Ores and Ingots but would like to not have an error spam my server console.

Seems to be an issue with it trying to unify tags that don't exist. I added an if statement to check it now, but if that doesn't help, try removing tags from the tagGen list that don't exist.