Xisuma's Custom Loot Tables Problem

I know this isn't exactly related to Bukkit/Spigot however I couldn't get in contact with the developer who made these custom loot tables, and this is my only place to post my problems because I have a Bukkit server. Have you ever heard of the Youtuber Xisumavoid? He and his team made custom loot tables which drop the mob's head after killing them. I am having a problem with the custom loot tables. Let me first give you some context. There are 3 folders which you install into your world data folder (advancements, functions, and loot_tables), and then you open up your world and put a crafting table into your inventory (I changed it to an anvil) which activates the loot tables. The problem I'm having is that whenever I install the loot tables it just spams errors in the console every single second saying "[mobs:variants: The dataTag does not match for 314337e8-b096-4b47-9032-6e87df9a9119]." The random string of numbers at the end changes every time. I can't figure out what's wrong because no one else is having this issue.

Links:
Xisuma's custom loot tables: http://xisumavoid.com/moremobheads/
My entire data folder for my server world: https://www.dropbox.com/sh/otfuc4xvj0x4xi1/AACqBHMG6aFQGDp2UL3_MFBwa?dl=0

 

@PuppersRbae
Please post your full console log.

 

https://www.dropbox.com/s/f46stbh089g1vbz/latest.log?dl=0