Why are people out to crucify Apple for a story that's still being resolved? The article clearly says: "... Due to a processing issue, your credit will be included on the security advisories in an upcoming update. We apologize for the inconvenience," Apple told him when asked why the list of fixed iOS security bugs didn't include his zero-day ..." "... We saw your blog post regarding this issue and your other reports…
It is entirely possible the researcher found something but didn't realize how deep the problem went. Apple may have released an incremental patch and is working on fixing a larger issue they found when digging into it.
When this has happened in the past, from the researchers perspective things seem quiet/delayed because we obviously can't share details of a larger vulnerability with them. All we can really do is ask for more time. In the end it all works out and they get paid out/credited for the original+follow on bug.