This sounds like a reasonable explanation. If I could, I’d ask that Facebook group to clarify, but none of my comments are being reviewed and approved for posting.Now I think of it, I think that's something Kal is calling "ebony" mirror as made up name. But from a company product perspective like Essilor Transitions or Zeiss, there is no such thing as "ebony" mirror or I didn't find any anywhere.
So may be his clear lens has silver flash mirror coating instead of AR but then that transitions to Black. you get some reflection.
One thing is to note is that when taking selfies, there is heavy reflection on mirror flash coating with transitions or without transitions. The mirror flash coating looks really cool in person on a clear lens but if you are posting photos on social media, people are going to think you went cheap and not applied AR coating.