The work on DNS-SD privacy is part of the general effort to reduce metadata leakage in the lower layer networking protocols. It is a complement to work on MAC Address Randomization, DHCP Anonymity, or DNS privacy.
By October 2017, I thought we had a good solution for DNS-SD privacy. We had a set of drafts that went through working group last call without many comments. And then, at the last minute, our colleagues at Apple objected that the specifications were difficult to implement, did not scale well, and did not align with other work on IOT privacy. So we are still working on the issue.