AndyB - Community Manager posted this on the thread below yours. The full post is in the Announcements - Midwinter Event: December 16 - January 6
“Well it looks like there was a mixup and the shard bonus isn’t going to be active for this season. We sincerely apologize for that. Quarantine brain’s got us all fogged up. Instead, we’ll be putting some things on sale; namely, all consumables are 30% off (PvP Insurance is 50% off) and we’re putting all the Hoards back up for the rest of the event, plus a 10% discount on top of that. The Hoards sale will be active as of approximately 9:00 AM EST tomorrow, December 17. Thanks everyone. Happy holidays”.
I took it to mean that since there are no new boxes to open, the buff isn’t turned on either.