The cards usually fix themselves after another review or 2. Here’s the positive spin – this is more common than I realized. It’s a chore to sort through posts about learning steps/intervals changing, because most of them turn out to be non-problems, but I did some creative searches and followed the breadcrumbs to pull up a few other examples of this happening. [I suspect this happens much more frequently than that sample, but folks just don’t notice.] Every time, it has fixed itself.
I don’t know how many cards this potentially impacted, but if you are worried about them, you could probably track them down with some careful searches (targeting cards that were introduced in a certain timeframe, still in Learn, have certain interval lengths, etc.), and “graduate” them manually using “Set Due Date.” Let me know if you want to explore that.
I suspect how much that would manifest and how much you would notice would depend on how much you change the steps. In your example, changing them multiple days seems like it could impact something. That’s not a reason to never change your learning steps, it’s just a reason to be cautious and anticipate some fluctuations.