When editing an item with "/item entity @s weapon.mainhand" with any item_modifier, the player's hand will go through the picking up new item animation, despite no new item having been picked up. This is extremely annoying when it comes to immersion in datapacks, as it is quite jarring having the player seemingly pick up the same item over and over again every few seconds / however often the item will be updated. This can be annoying for compass tracking / waypoints creation, some kind of weapon enchantment randomizer, and various animations which are created through editing the texture values of the item.

Turns out the glitch is also audible - and is present with the loot replace command in 1.16.4 as well as the 1.17 item command - any time an item is replaced by itself with any of these commands, it also place the picking up sound, which in datapacks causes a loud buzz anytime someone is affected by the commands multiple times in a row, cpletely breaking the immersion of the game