The bug

If you drop an item from the Creative inventory by dragging it over the edge of the inventory panel or by pressing Q while hovering above an item, it disappears after one minute. This does not happen if you drop the item with Q while not in the inventory.

This is problematic since it breaks despawn timer mechanisms.

This might be intended, but if so, it seems inconsistent that this happens only when dropping items out of the Creative inventory.

To reproduce

1. Switch into Creative mode
2. Drop an item by dragging it over the edge of the Creative inventory panel
3. Wait one minute
   → The item disappears

Videos

by cubfan135

https://www.youtube.com/watch?v=ynmw3S2mLHM

by andreasxp

https://youtu.be/cg_aVnuvZxc

Original description

If you drop an item or block from your inventory, it despawns after 5 minutes.
However, if you drop 2 - 64 items (so they group up) items despawn only after 1 minute.

I was only able to reproduce this bug in the attached world. I also pruned the world to check if that fixes the bug, but no. Here is a video of a stack of blocks despawning in 1 minute.

I've attached the world save where this bug is present.