This isn’t a Bug report of its own, but rather, at list of bugs that are related by the title of is issue.

Basically, there seems to be an issue with how items are handled in format versions above 1.16.100, which causes the issue. It is likely that these items use newer components and can’t be downgraded easily. The most likely thing to happen is a fix. Issue: MCPE-178674

The issue seems to have started by the time 1.20.0 was on its preview cycle. The bug seems to be found by Rainvay when she notices certain items aren’t scaled correctly when using HD textures. Issue: MCPE-169754

This also caused their first person animations to be incorrect. This was found by Strawberrymilk. Issue: MCPE-172710

And lastly, these items also can’t have their rarity changed without a language file through resource packs starting in version 1.21.30. This was found by AgentMindStorm. Issue: MCPE-185729

Please note that the items worked fine in older versions. It’s only by the time 1.20.0 was being tested in previews that the issue started.

If the issue persists, these items may be more and more broken.

(Temp: for Mojira Mods: I can’t seem to list any version above and below 1.21.44. Can you do that for me, please?)

Here are the broken vanilla items as of 1.21.44:

(Note: anything in parentheses aren’t always useful)

• All Music Discs
• Wind Charge
• Campfire
• Kelp
• Sugar Cane
• Brewing Stand
• Item Frame
• Redstone Repeater
• Redstone Comparator
• Hopper
• String
• Cauldron
• Cake (Sadly…)
• Nether Sprouts
• Flower Pot
• Chain
• Warped fungus on a Stick (Somehow)
• Coal (How???)
• Charcoal
• Snowball
• All Arrow variants (Normal and Tipped)
• Apple
• Trial Key 
• Ominous Trial Key
• Wolf Amour (???)
• All Bundles (Normal and Dyed)

How to Reproduce

There are many ways to visualize the bug for youself.

For the broken animations, hold any of the listed vanilla items and observe the bobbing and attack animations then, compare it to unaffected items. This also affects addon items made with a format version of 1.16.100 and above.

For the huge items bug, hold any of the listed items (or with custom items) with upscaled textures made with a format version of 1.16.100 or above (it doesn’t have to be detailed, just above 16x. I would recommend 32x for the items) then, observer the hilarious yet unintentional bug.