Signs appear blank when replaced by a command block immediately after they are broken

How to reproduce:

/give @s minecraft:command_block

1. Put in the command block the code:

setblock ~ ~ ~2 oak_wall_sign[facing=north]{front_text:{messages:['{"text":""}','{"text":"Example","color":"red","bold":true}','{"text":""}','{"text":""}']}} keep

1. Set the command block in repeating mode always active

2. Try to break the sign 

3. The text of the sign won't show it but using: /data get block <coordinates> you can check that the nbt data of the text has to be showed

4. In fact when exiting and re-entering the world the sign will show the text correctly

Expected Result:

The sign even if destroyed and replaced should show the text

Onedrive video:

BugMinecraft.mp4