I give up. I can’t figure this out. I tested it on my deck, which has two subdecks, each with five cards. I added five to one subdeck and removed the ones that had five. Theoretically, the new cards didn’t change at all, and both subdecks had five.
But no matter what I did, the order always looked like this: a5, a1, bn4, bn5, bn1, a2, a4, bn3, bn2
I set: Options for D \ New Cards \ Insertion order = Random
I selected the entries and re-sorted them, as you showed in the screenshot when adding them. But it turns out that the order doesn’t affect the cards it gives. It’s most likely a matter of time, but I won’t wait another hour and then test.
And it’s good that when I filtered the entire deck, it actually selected everything randomly!
At least this way you understand what might change the order, rather than the current situation where it stays the same for about an hour.
Let the developers explain what they’re doing and whether this was the case in older versions; I only have the new one here.