Select the shulker box in the backpack and quickly right-click twice to the empty slot.The server will crash.
this is log:
2023-08-22-7 (1).log
this is crash report:
crash-2023-08-22_23.19.29-server.txt
The error message reported by the server is that:"Encountered an unexpected exception".
quickshulker version:1.4.1
mc server version:1.19.3
java version:18
Hope for a quick solution,thanks.

And after restarting the server, the shulker box will also disappear.

Here are the video actions of the bug in the single archive and the report of the crash:
latest.log
https://github.com/kyrptonaught/quickshulker/assets/112075675/0b0507ce-1044-4f13-997d-8a8843caaa20
After this bug is caused in single-player mode, the world will probably: "locked by another running instance of Minecraft".As shown in the video.