The listings will be a little wonky for the next 2 months. Lots of 1st party, bigger content so the rest of the drops are going to be lighter. They probably wanted to count it as part of drop 1 to make it more appealing since you don't need to list 2 big full price games on the 2nd drop, so it probably just barely made the cutoff. And we know December is likely to get just 1 drop, since they do that every year, so letting you know in advance that it will likely happen again. After Stalker 2 and whatever else, we'll get 1 drop in Dec with Indiana Jones and whatever else.
But yeah, usually it's just 1 drop every 2 weeks. The onslaught of larger games is just requiring a tiny bit of tweaking on how they list it.