Before Continuing:

• Check you are using the latest version of the mods and its dependencies
• Always include a latest.log if you are crashing
• Remove known hacky mods such as: Optifine, Fabric API/Connector on forge, and every kind of hybrid server like Mohist and Velocity. None of these are supported. Also try without other lesser usual suspects like Sodium and Lithium.
• If you are unsure which mod is the culprit.
  Disable all of your mods and enable them 1-2 mods each time to isolate the culprit
• Confirm that there is no existing issue with a similar description submitted in the list of issues.

Version

1.20.1-FABRIC

Supplementaries Version

supplementaries-1.20-3.1.37

Moonlight Lib Version

moonlight-1.20-2.16.2

Describe Issue

So, sometimes when you breaking the busket one of the slots inside becomes empty. A managed to replicate this pretty consistenly like this:

• Fill basket with 6 stacks of same food
• Eat 1 item from any stack, and another from another stack
• Place basket
• Break basket
• 1 stack of 63 stacked with another, effectively voiding 62 items

doesnt seem to be an issue in 1.21.1. ill try 1.20 later

Yeah, I checked 1.21.1 as well, and it works fine there. I also recorded a video of the bug in 1.20.1:

Does it still happen in survival?

Yes, it does.

check new version. also quiver

It's fixed, thanks!