Hello
There seem to be a bug or something Wrong when it comes to replacing a wall type with something else when using the fill command. This is the command I use, /fill -4 83 73 26 54 73 polished_blackstone_brick_wall 0 replace cobblestone wall 7. I don't know if the command is either broken or I must've put in the command wrong. That is all I'm asking.

Steps to Reproduce:
1. Place a wall like a stone brick wall. Put around 5 or more together
2. Type in the fill command which replaces the existing walls you placed with another wall type or a block of your choice. The command should be like /fill [x y z] [x y z ] [block of your choice] 0 replace cobblestone_wall [0-8]
3. After you typed in the command, press the enter button
Observed Results:
All the stone brick walls or any wall type is not replaced with your block or wall of your choice

Expected Results:
All the stone brick walls or any wall type should be replaced with your block or wall of your choice when using the fill command.