Got the same problem but with the Mercy skin. Watched all of the streams so far, much more than 15 hours and not gotten the Mercy one yet.
However, the Mercy one might be bugged as I can’t find anyone who has gotten it so far.
Symmetra too, I have it, but some people don’t.
I got Symmetra after the second stream of South America, so my guess is either the Korea or the China event didn’t accumulate view hours, as people only have problems now.