I made a shop category for music disks. Every time I tried opening the music disc shop it would through a null pointer exception. I cross checked the id name I was using with the spigot material name page provided in the config and everything matched. I test each disc by having it be the only item in the category and the only discs preventing me from opening the disc shop were discs 11 and 13.
Minecraft version: 1.14.4
GUIShop version: 7.3.2
Error in console when trying to open music disc shop:

Screenshot of shop config:

There was also this warning in the console when the plugin started up:

Everything else has been working smoothly thus far!