That doesn't make sense, they are still holding a very large amount of it, why would they put this out and decrease the value of their own holdings?
Contrast with the scenario where they keep doing it, steadily increasing their bitcoin holdings and even seeing the proportion of sales using bitcoin increase… and THEN hit a wall, not of their own choosing, and see the value collapse.
Even if they are not dumping their holdings at all, there's still a case to be made for pulling a plug at a time they control, over an amount they control. If it collapses, they can put a hard limit on how much they lose: that being, the previous value of their entire bitcoin holdings.