It's not the same day. I noticed that the reset for my time zone is at 1 pm, my gf lost her Avian as well since she hadn't logged in at the time of the giveaway, which was a small window between the end of maintenance and the 1 pm daily reset...she did, however, receive her Burstinatrix reward. It's always been like this, it's most noticeable during Duel-A-Thons.
It is so strange. I play every evening (because some people has to work during the day) and it clearly says they give out foil cards according to a schedule and you can claim them from your gift box. So it should be there waiting for me.
During duel-a-thons you have an entire day to fill your dueling meter. You log in, ooh there is a duel-a-thon, lets get down to business (even if you only have few hours left). Check date and time of notification, you cannot send it at that time and then say you can only claim the price if you are online at that precise same time. If its that strict, they should sent notification evening before.
I agree, it's a small window of opportunity and there's no notification beyond the unannounced notification on start-up. I don't know the criteria behind their updates or gift releases, so I just try and log in as many times as possible during the day. I work too, so I know the struggle xP.
On the first day of a Duel-A-Thon, there is usually a period of time in which I can fill up my meter before the 1 pm reset, I see this as Day 1. The meter will then reset at 1 PM and this would be Day 2. I think this time period (Sometimes starting at 12 am) is the exact time at which these announcements are made...so it's a 13 hour window at most...8 of which we are probably sleeping.