The bug
When renamed with a name tag, armor stand will not show the nameplate above its head until CustomNameVisible:1b
is set.
To reproduce
Place an armor stand
Rename it with a name tag
Use the following command:
/data merge entity @e[type=minecraft:armor_stand,limit=1,sort=nearest] {CustomNameVisible:1}
Linked issues
is duplicated by 3
testing discovered 1
Attachments
Comments 50

Please do not mark unreleased versions as affected.
You don't have access to them yet.
--- I am a robot. This action was performed automatically.
/entitydata @e[type=ArmorStand,r=5] {CustomName:"Name Here"}
Thx, I know this command, but that doesn't change, that you can't rename an armor stand with a name tag as you could before (and should be able to).
Also this bot-thing is silly. Why do we have access to this version number in the affected versions list, when we aren't supposed to mark it with it?

The bot thing is not silly, because it fixed your mistake.

Renaming armor stands by name tags was never possible.

Can confirm in 23w03a.

Can confirm in 1.20.4

confirmed in 1.20.6

affects 1.21

affects 1.21.3
Use
while standing within 5 blocks of the armor stand you want to change.