Fill Command always shows error "Cannot place block outside of World"

Every time we use the fill command inside our realm we can only keep it in a small distance, even though I can see in the world chucks where the command should end. I'm thinking this is a bug, because it doesn't make any sense.

My chuck rendering is all the way up, and I can see where command is supposed to end. However, never reaches that point due to me shortening the distance from the error. Please fix thanks.