The bonus buff begins in the Americas region this Saturday, July 9 at 12:01 a.m. PDT and ends on Sunday, July 10 at 11:59 p.m. PDT.
This buff affects all events which grant Blood Shards, including Bounties, Rifts and Greater Rifts.
I believe this is Tyvalir's first post since being back as well. Thanks for coming back with style!