This is an issue posted by another user in the GUIShop discord, I'm adding it here so that it can be more easily managed – A248

no matter what the 89th entry is (i've tried perfectly valid ones that I know work from earlier in the config), it doesn't load in any items past the 70th if I have an 89th entry at all and throws:

yaml validators are fine, i'm certain the 89th entry isn't invalid or anything.

section of config in question (88):

  '87':
    type: SHOP
    id: QUARTZ_SLAB
    buy-price: 2.0
    sell-price: 1.0
  '88':
    type: SHOP
    id: QUARTZ_SLAB
    buy-price: 2.0
    sell-price: 1.0

Stacktrace: https://pastebin.com/9QUqnrFL
Config: https://pastebin.com/HQTv5j21

Paper 151 - 1.15.2
GUIShop 7.3.8

I've found that the shop's still loading, but the items don't appear in the GUI - if I click on the blank item slots, they still function partially.
Since it's hard to explain in text, here's a video:
https://www.youtube.com/watch?v=BtRzC2GOuIc
Lots of errors in console (included there) whenever clicking on anything and my inventory and any purchases made are wiped if made from the 2nd or 3rd page.

This will be reviewed for 8.2.