The Bug

This relatively frequent bug causes items to get stuck in an inventory slot. These items become immovable, preventing stacking with other items, and it's not possible to occupy the slot with a different item. All three of these points can be observed in the video.

Informations

• The bug occurs on the PS4, PS5, and Windows versions.
• The bug occurs in regular worlds and Realms.
• So far, I've only observed the bug in Survival mode, but I don't rule out the possibility of it appearing in Creative mode as well.
• The only way to get rid of the bug is to exit the world and rejoin it

Reproduce

I couldn't find a consistent way to force the bug. It seems to occur when attempting actions such as placing items from the inventory into a chest or picking up items from the ground. In the video where the diamond was bugged, I intended to place it in a chest alongside other diamonds, only to realize that the item couldn't be moved. In the video with the bugged stone bricks, I was mining and simultaneously collecting them until I noticed that the stack in my hotbar got stuck at 63 stone bricks and wouldn't increase anymore. Any additional bricks I picked up went into a different slot. The bugged stone bricks were unmovable, as shown in the video. I've encountered this bug in various situations, often when organizing my inventory or picking up numerous items.