If you try to modify the data of a player with /data it doesn’t work

How to reproduce the bug

Try modifying player data using /data

Example: Modifying the selected slot by modifying SelectedItemSlot to 4 (5th hotbar slot)

/data modify entity @s SelectedItemSlot set value 4
/data modify entity @s {SelectedItemSlot: 4}

Expected Behavior

It changes the player NBT (In the example above if it worked as expected it would change the players selected hotbar slot to the 5th slot)

Actual behavior

It doesn’t work