The stack size is reset.

For example, I created a custom item based on "paper" (set as the parent item) with a maxStackSize of 10,000; however, the items stop stacking whenever the server is restarted (or similar events occur).
If I open the Custom Item Manager and select "Edit" followed by "Update" for that item, they begin stacking again.
Could you please look into this?

Changed Status from Pending to Work in Progress