I believe the main reason for that to end a bit later than what they anticipated was the fact that it wasn't clear what they wanted with the topic of it. When you do something like Halloween or Christmas or valentines day etc etc, you know there is a topic for it and it's clear what they want from us as well. But that August one that had to be extended wasn't clear at all and it was just august, that's it.
Halloween, Christmas and Valentines events are far from now but so discussions about them right now can go in to the air and be forgotten. I believe Roobet marketing team do remember about their past marketing programs around those special days and they will come back with similar or new programs to celebrate those days.
Rules can be changed by the team but with public announcement, it will not be big issue for participants. Events and marketing programs are enjoyable, not to feel headache about them.