How many daily quests are stored internally?

I always thought when you reach the cap of 3 open daily quests, you receive one new quest once you clear one (provided you haven't received one that day because of the cap).

But today, when i hadn't cleared a quest for 2 days while at the limit (and having been in the game each day), i cleared 2 quests simultaneously and both were replaced. This rises questions.

• Since it's not just the one from that day, how many quests are stored internally ready to be received once there is enough space in the questlog?
• is this dependant on logging into the game on each respective day, putting the quest for that day in some kind of queue?
• is it dependant on clearing multiple quests simultaneously, meaning quests only reload once per day the first time at least one quest is cleared (assuming there are enough quests in queue)?
• if the answer to the previous question is yes, does this empty the queue or does it keep accumulating quests to be received?

As an example where the last point matters, let's say i have 4 quests in queue, then clear 2 simultaneously. The next day, I clear 2 quests simultaneously again. If the queue resets, only one new quest will be received.