Infinite Concrete powder Generator Isn't so Infinite

More detailed report in attachments below
Description: I went on minecraft Realms and one of my friends had built a printer using concrete powder, and I decided to use it to make a red sheet of concrete. I then looked at the "Ink cartridges" I will call them had a weird patch of air despite being an repeat unconditional always active command to set block powder there. However I noticed a fix to it by breaking the block below it.
Steps to activate:
1. Create a concrete powder "spawner" using /setblock ~ ~-1 ~ minecraft:concrete_powder with a repeat command block.
2. Move the powder around.
3. Stop movement.