Steps to reproduce:
/summon minecraft:falling_block ~ ~ ~ {BlockState:{Name:"minecraft:diamond_block"},NoGravity:1b,Time:1}
/data modify entity @e[type=falling_block,limit=1,sort=nearest] BlockState.Name set value "minecraft:gold_block"I'd expect the diamond_block entity to change into a gold_block, but it doesn't visually. The block id inside (using /data get) does show "minecraft:gold_block".
Linked issues
duplicates 1
Comments 3
The reason for MC-72849 being closed as Won't Fix is because modifying the NBT of an entity during its lifetime is a bit hacky and as such not supported, because otherwise it would open a whole can of worms. Here's a more detailed explanation by Dinnerbone: https://www.reddit.com/r/MinecraftCommands/comments/9ty42s/data_modify_is_irritating_me_today/e91rwc7/?context=3
Wow! Finally someone kind enough to point me to an answer for not being able to edit player NBT!
The weirdness around editing falling_block nbt probably has something to do with this.
For anyone finding this issue, as of 1.15.2 a neat workaround involves force loading a chunk far far away (outside anyone's render distance), summoning and modifying the falling_block there and then TPing it back into the right position.
The fact that teleporting a falling block doesn't visually move it either (and just makes blocks appear seemingly out of thin air at the destination) is probably related to this.
And damnit, of course I find an already existing issue after posting, while I couldn't find anything during the first search. MC-72849
The mentioned issue is closed as won't fix without reason, which quite a few players commented on for reconsideration or at least an explanation.