The bug
On 2020-04-21 the format of player head texture data changed significantly across all versions, breaking existing commands. It seems to include a lot of duplicate data now as seen in the attached image. Certain fields such as timestamp are missing. The impact of this change is not completely clear yet, more testing needs to be done.
Cause
The response of "GET sessionserver.mojang.com/session/minecraft/profile/<uuid>
" has changed. The expected response is documented here: https://wiki.vg/Mojang_API#UUID_-.3E_Profile_.2B_Skin.2FCape
How to reproduce
Give yourself a player head and place it on the ground
/give @s player_head{SkullOwner:"steve"}
Check the texture data of the block
/data get block ~ ~ ~ Owner.Properties.textures[0].Value
Notice that the encoded JSON object is much larger than before, decoding it gives you a similar result as the attached image.
Attachments
Comments


Could you please make the url support data:image/png; ?
Players cannot see the texture if there is no Internet connection now.
At least 6 maps on Java Realms are broken (almost definitely more), and this may break many maps published since 1.8 that use player skulls.