Leak make sense, especially since last Ion comment about launching Heroic and Mythic same week - this move is necessary only with DF launching week later than SL, because SL already launched in last possible (within reason) week.
But it's not that hard to guess Game Awards date as many of you think. Just look on last few years: since 2015 it's always Thursday, 2015-2018 first, 2019-2021 second Thursday of December.