The bug

If a player (who is not an operator) attempts to right click a decorated pot which is in spawn protection with an item, the client will think the item was put into the decorated pot (count visually decreases). Clicking into the slot again, or by other common means of solving this type of issue shows that the items were never used up.

The pot of course remains empty, however the client also think the pot now has a certain amount of items in it, as seen by any further attempt at filling the pot will only decrease the stack up to a certain point and then stop.

Both of those issues can be seen in the video I have attached.

This issue also affects the Realms.