Can't see some items in shulker boxes 1.12

[Dainternetdude]

General Information

ViaFabricPlus 3.0.6
Minecraft 1.20.4
Fabric Loader 0.15.6

Bug Description

When playing on a server with version 1.12, some specific types of items do not appear in the list of items that are inside of a shulker box when hovering over it in any inventory. Upon placing the shulker box & opening it, the items are seen normally. Most Items do show up normally in the list as well. I have only seen certain items that don't want to show up in the list, including birch logs (pictured), light grey stained glass, & some types of fish.

I have also noticed that some items show up in the list as other items. For example, when hovering over a shulker box containing 5 granite, the tooltip states "Stone x5".

I have also noticed that in creative mode, empty shulker boxes have a tooltip saying "Coloured Blocks" & "Functional Blocks", but shulker boxes with invisible items inside do not have this part of the tooltip present, they simply display the name of the box.

Steps to Reproduce

1. Join server with version 1.12 in creative mode
2. Place empty shulker box and insert a log
3. Break the shulker box & pick it up
4. Hover over the shulker box item in your inventory & observe the tooltip, the log item will not be displayed in the list of items contained within the shulker box

Expected Behavior

When I look at the tooltip of a shulker box in an inventory it should display the contents accurately as it does when using a 1.12 client on the 1.12 server.

[Dainternetdude]

[Barvalg]

[Dainternetdude]

Is there anything you need from me? I can get a log file if it helps.

[FlorianMichael]

No thanks, we already know what the issue is.