Commands with items in containers aren't converted to item components

[LaserSlime]

Expected behavior

This command in a command block in 1.20.4:
/setblock -39 30 707 minecraft:hopper[enabled=true,facing=east]{Items:[{Count:41b,Slot:0b,id:"minecraft:blue_dye",tag:{display:{Lore:['[{"text":"- gɾɑпɫs ɫhɛ gɪƒɫ oƒ ᴜпժɛɾɯɑɫɛɾ","italic":true,"color":"gray"}]','[{"text":"ɾɛsρɪɾɑɫɪoп oпcɛ gɪνɛп ɫo ɫhɛ shɾɪпɛ","italic":true,"color":"gray"}]','[{"text":"ƅɛhɪпժ ɫhɛ ɛпժlɛss ɫᴜппɛl.","italic":true,"color":"gray"}]'],Name:'[{"text":"🌊","italic":false,"color":"aqua"},{"text":" "},{"text":"Λզ","bold":true},{"text":"ᴜɑ","bold":true,"color":"dark_aqua"},{"text":" ","bold":true},{"text":"Δᴜ","bold":true,"color":"blue"},{"text":"sɫ","bold":true,"color":"dark_blue"},{"text":" ","bold":false,"color":"dark_blue"},{"text":"🌊","bold":false,"color":"dark_blue"}]'}}},{Count:1b,Slot:1b,id:"minecraft:blue_dye",tag:{display:{Lore:['[{"text":"- gɾɑпɫs ɫhɛ gɪƒɫ oƒ ᴜпժɛɾɯɑɫɛɾ","italic":true,"color":"gray"}]','[{"text":"ɾɛsρɪɾɑɫɪoп oпcɛ gɪνɛп ɫo ɫhɛ shɾɪпɛ","italic":true,"color":"gray"}]','[{"text":"ƅɛhɪпժ ɫhɛ ɛпժlɛss ɫᴜппɛl.","italic":true,"color":"gray"}]'],Name:'[{"text":"🌊","italic":false,"color":"aqua"},{"text":" "},{"text":"Λզ","bold":true},{"text":"ᴜɑ","bold":true,"color":"dark_aqua"},{"text":" ","bold":true},{"text":"Δᴜ","bold":true,"color":"blue"},{"text":"sɫ","bold":true,"color":"dark_blue"},{"text":" ","bold":false,"color":"dark_blue"},{"text":"🌊","bold":false,"color":"dark_blue"}]'}}},{Count:1b,Slot:2b,id:"minecraft:blue_dye",tag:{display:{Lore:['[{"text":"- gɾɑпɫs ɫhɛ gɪƒɫ oƒ ᴜпժɛɾɯɑɫɛɾ","italic":true,"color":"gray"}]','[{"text":"ɾɛsρɪɾɑɫɪoп oпcɛ gɪνɛп ɫo ɫhɛ shɾɪпɛ","italic":true,"color":"gray"}]','[{"text":"ƅɛhɪпժ ɫhɛ ɛпժlɛss ɫᴜппɛl.","italic":true,"color":"gray"}]'],Name:'[{"text":"🌊","italic":false,"color":"aqua"},{"text":" "},{"text":"Λզ","bold":true},{"text":"ᴜɑ","bold":true,"color":"dark_aqua"},{"text":" ","bold":true},{"text":"Δᴜ","bold":true,"color":"blue"},{"text":"sɫ","bold":true,"color":"dark_blue"},{"text":" ","bold":false,"color":"dark_blue"},{"text":"🌊","bold":false,"color":"dark_blue"}]'}}},{Count:1b,Slot:3b,id:"minecraft:blue_dye",tag:{display:{Lore:['[{"text":"- gɾɑпɫs ɫhɛ gɪƒɫ oƒ ᴜпժɛɾɯɑɫɛɾ","italic":true,"color":"gray"}]','[{"text":"ɾɛsρɪɾɑɫɪoп oпcɛ gɪνɛп ɫo ɫhɛ shɾɪпɛ","italic":true,"color":"gray"}]','[{"text":"ƅɛhɪпժ ɫhɛ ɛпժlɛss ɫᴜппɛl.","italic":true,"color":"gray"}]'],Name:'[{"text":"🌊","italic":false,"color":"aqua"},{"text":" "},{"text":"Λզ","bold":true},{"text":"ᴜɑ","bold":true,"color":"dark_aqua"},{"text":" ","bold":true},{"text":"Δᴜ","bold":true,"color":"blue"},{"text":"sɫ","bold":true,"color":"dark_blue"},{"text":" ","bold":false,"color":"dark_blue"},{"text":"🌊","bold":false,"color":"dark_blue"}]'}}},{Count:1b,Slot:4b,id:"minecraft:blue_dye",tag:{display:{Lore:['[{"text":"- gɾɑпɫs ɫhɛ gɪƒɫ oƒ ᴜпժɛɾɯɑɫɛɾ","italic":true,"color":"gray"}]','[{"text":"ɾɛsρɪɾɑɫɪoп oпcɛ gɪνɛп ɫo ɫhɛ shɾɪпɛ","italic":true,"color":"gray"}]','[{"text":"ƅɛhɪпժ ɫhɛ ɛпժlɛss ɫᴜппɛl.","italic":true,"color":"gray"}]'],Name:'[{"text":"🌊","italic":false,"color":"aqua"},{"text":" "},{"text":"Λզ","bold":true},{"text":"ᴜɑ","bold":true,"color":"dark_aqua"},{"text":" ","bold":true},{"text":"Δᴜ","bold":true,"color":"blue"},{"text":"sɫ","bold":true,"color":"dark_blue"},{"text":" ","bold":false,"color":"dark_blue"},{"text":"🌊","bold":false,"color":"dark_blue"}]'}}}],TransferCooldown:0}

Should be converted to this when upgrading to 1.21.1:
/setblock -39 30 707 minecraft:hopper[enabled=true,facing=east]{Items:[{Slot:0b,components:{"minecraft:custom_name":'[{"text":"🌊","italic":false,"color":"aqua"},{"text":" "},{"text":"Λզ","bold":true},{"text":"ᴜɑ","bold":true,"color":"dark_aqua"},{"text":" ","bold":true},{"text":"Δᴜ","bold":true,"color":"blue"},{"text":"sɫ","bold":true,"color":"dark_blue"},{"text":" ","bold":false,"color":"dark_blue"},{"text":"🌊","bold":false,"color":"dark_blue"}]',"minecraft:lore":['[{"text":"- gɾɑпɫs ɫhɛ gɪƒɫ oƒ ᴜпժɛɾɯɑɫɛɾ","italic":true,"color":"gray"}]','[{"text":"ɾɛsρɪɾɑɫɪoп oпcɛ gɪνɛп ɫo ɫhɛ shɾɪпɛ","italic":true,"color":"gray"}]','[{"text":"ƅɛhɪпժ ɫhɛ ɛпժlɛss ɫᴜппɛl.","italic":true,"color":"gray"}]']},count:41,id:"minecraft:blue_dye"},{Slot:1b,components:{"minecraft:custom_name":'[{"text":"🌊","italic":false,"color":"aqua"},{"text":" "},{"text":"Λզ","bold":true},{"text":"ᴜɑ","bold":true,"color":"dark_aqua"},{"text":" ","bold":true},{"text":"Δᴜ","bold":true,"color":"blue"},{"text":"sɫ","bold":true,"color":"dark_blue"},{"text":" ","bold":false,"color":"dark_blue"},{"text":"🌊","bold":false,"color":"dark_blue"}]',"minecraft:lore":['[{"text":"- gɾɑпɫs ɫhɛ gɪƒɫ oƒ ᴜпժɛɾɯɑɫɛɾ","italic":true,"color":"gray"}]','[{"text":"ɾɛsρɪɾɑɫɪoп oпcɛ gɪνɛп ɫo ɫhɛ shɾɪпɛ","italic":true,"color":"gray"}]','[{"text":"ƅɛhɪпժ ɫhɛ ɛпժlɛss ɫᴜппɛl.","italic":true,"color":"gray"}]']},count:1,id:"minecraft:blue_dye"},{Slot:2b,components:{"minecraft:custom_name":'[{"text":"🌊","italic":false,"color":"aqua"},{"text":" "},{"text":"Λզ","bold":true},{"text":"ᴜɑ","bold":true,"color":"dark_aqua"},{"text":" ","bold":true},{"text":"Δᴜ","bold":true,"color":"blue"},{"text":"sɫ","bold":true,"color":"dark_blue"},{"text":" ","bold":false,"color":"dark_blue"},{"text":"🌊","bold":false,"color":"dark_blue"}]',"minecraft:lore":['[{"text":"- gɾɑпɫs ɫhɛ gɪƒɫ oƒ ᴜпժɛɾɯɑɫɛɾ","italic":true,"color":"gray"}]','[{"text":"ɾɛsρɪɾɑɫɪoп oпcɛ gɪνɛп ɫo ɫhɛ shɾɪпɛ","italic":true,"color":"gray"}]','[{"text":"ƅɛhɪпժ ɫhɛ ɛпժlɛss ɫᴜппɛl.","italic":true,"color":"gray"}]']},count:1,id:"minecraft:blue_dye"},{Slot:3b,components:{"minecraft:custom_name":'[{"text":"🌊","italic":false,"color":"aqua"},{"text":" "},{"text":"Λզ","bold":true},{"text":"ᴜɑ","bold":true,"color":"dark_aqua"},{"text":" ","bold":true},{"text":"Δᴜ","bold":true,"color":"blue"},{"text":"sɫ","bold":true,"color":"dark_blue"},{"text":" ","bold":false,"color":"dark_blue"},{"text":"🌊","bold":false,"color":"dark_blue"}]',"minecraft:lore":['[{"text":"- gɾɑпɫs ɫhɛ gɪƒɫ oƒ ᴜпժɛɾɯɑɫɛɾ","italic":true,"color":"gray"}]','[{"text":"ɾɛsρɪɾɑɫɪoп oпcɛ gɪνɛп ɫo ɫhɛ shɾɪпɛ","italic":true,"color":"gray"}]','[{"text":"ƅɛhɪпժ ɫhɛ ɛпժlɛss ɫᴜппɛl.","italic":true,"color":"gray"}]']},count:1,id:"minecraft:blue_dye"},{Slot:4b,components:{"minecraft:custom_name":'[{"text":"🌊","italic":false,"color":"aqua"},{"text":" "},{"text":"Λզ","bold":true},{"text":"ᴜɑ","bold":true,"color":"dark_aqua"},{"text":" ","bold":true},{"text":"Δᴜ","bold":true,"color":"blue"},{"text":"sɫ","bold":true,"color":"dark_blue"},{"text":" ","bold":false,"color":"dark_blue"},{"text":"🌊","bold":false,"color":"dark_blue"}]',"minecraft:lore":['[{"text":"- gɾɑпɫs ɫhɛ gɪƒɫ oƒ ᴜпժɛɾɯɑɫɛɾ","italic":true,"color":"gray"}]','[{"text":"ɾɛsρɪɾɑɫɪoп oпcɛ gɪνɛп ɫo ɫhɛ shɾɪпɛ","italic":true,"color":"gray"}]','[{"text":"ƅɛhɪпժ ɫhɛ ɛпժlɛss ɫᴜппɛl.","italic":true,"color":"gray"}]']},count:1,id:"minecraft:blue_dye"}],TransferCooldown:0}

Observed/Actual behavior

It stays the same.

Steps/models to reproduce

1. Create a world in 1.20.4 and put the first command in a command block
2. Upgrade the world to 1.21.1
3. See how it stays the same

Plugin and Datapack List

No plugins

Paper version

version
[21:05:11 INFO]: Checking version, please wait...
[21:05:12 INFO]: This server is running Paper version 1.21.1-57-master@b483da4 (2024-09-01T18:09:05Z) (Implementing API version 1.21.1-R0.1-SNAPSHOT)
You are running the latest version
Previous version: 1.21.1-13-7c9240f (MC: 1.21.1)

Other

PaperMC/DataConverter@942697c This commit fixes this issue. Consider merging this into Paper.