Hi, I always add 10 cards at a time to my stack and review them shortly after. But today being the day of the first expiry for those cards, I expect there to be 10 orange cards in the stack but instead there's only 2???

All the 10 new cards have been reviewed within at the very least 10 minutes of eachother, but still there are still only 2 expired cards and it's been like 9 hours since the proposed due date?

Assuming all cards are reviewed at least 10 minutes of eachother (more like less than 5 minutes though) Why do not all cards added in the "set" of 10 expire close to the same time like they should?

It's also sometimes weird numbers of cards like 7 or 9 and the others come a day later, I don't really understand why??? I've never ever touched the "easily remembered" button either, can someone please explain to me how the card expiring system works? thanks.