The wrong current URL is https://minecraftnetassets.z13.web.core.windows.net/minecraft-net-assets-container/name.png
The correct URL would be https://minecraftnetassets.z13.web.core.windows.net/minecraft-net-assets-container/1.21.5_pig-desert.png
Instead you can use something like that:
/tellraw @a [["String-Text "], [{"text":"Component-Text"}]]
(I've just made a list for every single tag)
You need to use in 25w02a the command from 1.21.4.
The following command stil works:
/data modify block ~ ~ ~ front_text.messages[0] set value '{"text":"Hello","bold":true}'
Edit: This command adds the message as a string, which means that "{"text":"Hello","bold":true}" is shown on the sign instead of "Hello"
The pigs in the Screenshot have modified NBT ({NoAI:true})
The bug is working again. Maybe it is related to the bug [MC-273960]. I uploaded a video in the correct version of Minecraft with this bug. In the video I use a data pack that simply shows the contents of the pot.
Okay, I can't recreate it myself right now. Maybe I chose the wrong version of Minecraft to check.
Affects Preview 1.21.10.21 with format_version 1.20 in Behavior Packs and in the UI of the NPC
Can confirm. Even in 1.21.6.