Failed to invoke armor_stands inside blocks

When we try to invoke an armor_stand (using the / summon command) within a block to create some decoration, the entity is moved to some empty place because the space is already occupied.
How to make:

1) My goal is to invoke an armor_stand within these blocks.

2) This is the command I will use.

3) When you press the button, the Armor Stand is moved out of the block automatically, like a bug.

x

1) In a second demonstration, changing height Y to +1

2) The block is moved upwards, and ends up not staying in the desired place.