Command block's nbt cannot copy before second save

1. Write something in the command block.
2. Press done button.
3. Move the cursor it and press ctrl and the mouse wheel simultaneously.
4. Place the block you have in the main hand.
5. Text field inside the block you placed is empty.
6. Open 1.s command block UI.
7. Repeat 2~4's action.
8. In the text field in the second block you placed is what you wrote in 1.
   Chain and repeating, too.