Anniversary Sale is coming, for sure, but I guess that missing Daily Deal are nothing more than just GOG team mistake (again). I'd not be surprised if they just start a new Daily Deal today and keep rolling them the next week or two, until Big Sale begins.
I remember reading a post, where somebody linked screenshots of mails from when GOG went live. And I think the consensus was that GOG will celebrate its anniversary, sometimes in October, which is the date when the GOG store went out of beta. Do you happen to know the exact date when that happened?
I ask because I find it kind of interesting that the Thronebreaker game will be released on the 23 of October. Too close to be just a coincidence?