Yeah but it's a few pages and not really a big hinted lore drop. It's not the kind of thing I'm talking about. Doflamingo's is much larger and tied to Law's. BMs heavily has to do with a potential future plot to this day. Kaido's has heavily alluded to mysteries with Wano and Rocks.
Why its so late, I have no idea, but ideally stuffing a FB directly in the middle of the fight just might have been what Oda would have wanted to do. Doing it right after G5 would have taken away from G5 imo. Doing it now and potentially before "awakening" or what have you could fully reveal history behind his character and define his villainy.
That's just my thought on it. I really don't know if it's happening, but I still find Drumz and Redon's hints to be pretty weird. Anyway, we should get some hints tomorrow, maybe they allude to this or not, or they just mean nonsense lol.