Thanks for taking the time to open a bug report!

Describe the bug
"Inventory" option to click on a item in inventory it's not working in gamemode creative

To Reproduce
Steps to reproduce the behavior:

1. Add the "inventory" option to an item
2. Click on it in gm 0

Expected behavior
Should execute the command you've set

Screenshots
https://youtu.be/Jp8PFKeUlUA

Pastebin
Even if it is not related to the problem, please include ALL configuration files in separate Pastebin.com links as well as any related error codes from the console window.

Please complete the following information:

• Resource Version and Build Number: 5.2.6 b855
• Server Version 1.19.2

Additional context
Add any other context about the problem here.

This is intended, not a bug.

If you have the inventory-modify itemflag on an item and enter creative mode you will have your inventory force-closed.
This is to prevent exploits as creative mode breaks the inventory-modify flag as Mojang did not properly program their creative interface.

This is a known issue with many plugins so I simply opted to disable item interaction entirely. I would recommend using a creative mode alternative if it is super imperative such as FakeCreative.

Otherwise removing the inventory-modify itemflag will also solve this.

I hope that answers your question and I apologize that there is not a better solution. I am watching Mojang's dev branch so if they end up ever patching the many bug requests in regard to this issue I will be sure to update ItemJoin respectively.

EDIT (12/10/22): Marking as answered due to inactivity, please feel free to re-open this issue if you still need help.