Thanks for reaching out -
Yes it's valid. (I'll attach proof)
I've done some more research on it and it seems that you can't modify the config after doing the in-game menu edits.
So when you modify the config, reload the plugin, go in game and use admin permission to edit the rewards, IF you go back into the config to make manual changes it and reload it will break everything, (yes the config is validated)
I have redone it so many times and found that the only way it works is if you edit the config first and reload it- then go into the game and add all skinned items/commands. If you manually add the items (while ensuring correct formatting) it will not allow it to load in the console, it will provide the above attached error.