No is NOT a bug , if u read properly (not sure if people can still do it nowadays apparently...) they clearly state that the build is working as intented in all its complex iteractions.
I disagree. Ring of Emptiness shouldn't work with pets. Hence the Blizz explanation:
,,We wanted to share our thoughts on this today and reassure the Witch Doctor community that, at this time, we have no intentions to make changes to Spirit Barrage (Phantasms) or its currently existing interactions with items such as Mask of Jeram, Ring of Emptiness or The Barber.
While this is somewhat inconsistent philosophically from the changes that we’ve made in the past regarding this skill and rune combination..."
So, they didn't say that the build is working as intended, quite contrary.
But: ,,we looked at the situation objectively and asked ourselves a couple questions:
Is it fun?
Is it balanced?
Ultimately, we’ve decided that the answer to both of these questions is yes, and there is much higher risk in adjusting the balance of this skill or the other items than there is to let the community continue to enjoy this fun and unique build."
So they decided to leave it as it this, because it doesn't seem to be unbalanced and players like this build.