this is an issue for registering (custom) blocks from multiple servers, which is more of an issue for proxies using dragonfly's API, but is still a design flaw

implementation can be seen in olebecks fork:

https://github.com/olebeck/dragonfly/blob/5f35073ae6c98466dd6feab3dbe81953fc3c52ae/server/world/chunk/block_registry.go