Steps to reproduce

• Generate a world using the Debug world type
• /tp to x=0 z=1496
  You will notice that in each of the rows of blocks there are 8 brewing stands
• Open F3, look at one of the brewing stand and look at the info on the right hand side of your screen
  You will notice that all the brewing stands show the following info:

Block: minecraft:brewing_stand/0
has_bottle_0: false
has_bottle_1: false
has_bottle_2: false

The point of this world type is that all possible blocks (in other words, every possible id and data value) are generated in each row, but in a row, brewing stands generate 8 times despite being exactly identical.