When you break a player head with the tag note_block_sound
set, which makes the note block placed below produce the specified sound as expected, the resulting item doesn't have the tag.
To reproduce
Stand on top of a note block
Run the command
/setblock ~ ~ ~ player_head{note_block_sound:"minecraft:ambient.cave"}
Right-click the note block, this will cause a spooky sound to play
Switch into Survival mode
Break the head
Select it in your hotbar
Run
/data get entity @s SelectedItem
Place it back on top of the note block
Right-click the note block again
Observed result
No sound is played and the result of the command is
{id: "minecraft:player_head", Count: 1b}
Expected result
A spooky sound is played and the result of the command is
{id: "minecraft:player_head", Count: 1b, tag: {BlockEntityData: {note_block_sound: "minecraft:ambient.cave"}}}
I couldn't reproduce that part. This command works fine: