Dunno if this is bug or intention, but
First day -> First sticker -> Second slot in calendar ??
Paying or collecting the joker should not be required if you play daily but apparently it is, or did I miss something??
If it is due to Earth time zones, that is still wrong. I don't know when exactly it has started, but I was online 15 hours ago and there was no event yet (I play only on PC), so it must have started LESS than 15 hours ago, thus it shouldn't be in second day of the calendar no matter the time zone.