I don’t know what started you on the idea that you’re dealing with interday learning cards here, but I don’t see anything that suggests you are. To be “interday” it is not enough just to be leftover in Learn from yesterday – the interval needs to cross the day boundary and be converted to 1d. That’s not what is showing up in your Card Info.
These are regular short-interval Learn cards, which you didn’t graduate to Review the day before, so they are now overdue. These “0 seconds” cards you’re concerned about are most likely 1s cards with fuzz applied – it’s a tiny step, with a tiny amount of fuzz, and rounding.
Your idea to flip between 2 cards until you get them is the opposite of what spaced repetition is designed to do. Anki will still do it for you, but I expect you’re only going to see the result you want if you only have 2 cards ready to study in Learn. Those 2 cards on their tiny intervals will always push to the front of the queue.
Once you have 20 Learn cards stacked up, you’re going to see them in the order that they finished their intervals – with fuzz applied to make sure you don’t see them in the same order all the time.
Other factors I’m not considering –
- You’re changing your learning steps while you have cards in Learn, which you should expect to result in skipped or repeated learning steps while those cards adjust.
- You’re using a beta version that has scheduling changes. But this behavior looks exactly how it always has, so I don’t have reason to think those changes are having any impact here.