Ore placement after bosses have been defeated

So, I made a stone variant that should be a perfect stone replica, which, after the Ender Dragon, Wither, Warden and Elder Guardian have been defeated, should be replaced with a custom ore. The block generates perfectly fine, yet after defeating the bosses, it doesn't replace itself with the custom ore I told it to replace itself with. Can someone help me with this? The block's ticking setting is at 20.

https://imgur.com/a/M1dEpnA