The 0 you see is the namespace. New feature in v21.x
When you see a bunch of null characters in the logs or state endpoint is is because the namespace is actually a 64bit integer, and that is the full binary representation, with the least significant bit being the one that would change for namespace 1, etc.
Edit: Sorry this part was already answered for you on the other linked thread. That’s what I get for half reading the question.