Yes, the overall thing you’re seeing here is fuzz factor. While it doesn’t apply to Learn cards, it does apply to graduating cards, including their Graduating and Easy intervals. The big change you’re adjusting to right now is that while fuzz has been there all along, under v3 it’s now showing on your grading buttons.
Ex. 1 – Graduating interval +/- fuzz, so 2 days is possible. You’ll be able to tell that’s what happened by looking at this card after grading it. If it has an Ease set, it graduated to Review.
Ex. 2 – No problem.
Ex. 3 – Same as Ex. 1, graduating interval +/- fuzz.
Ex. 4 – This is the only one that gives me pause. That definitely looks like it repeated your 2nd step. It sounds like you’ve ruled-out some of the common reasons for this – delayed syncing, changing learning steps – which can have quirky impacts on cards currently in Learn. However it also sounds like you were changing between Anki and scheduler versions while trying to troubleshoot.
It looks like that review was done much later than the others you were concerned about. So if this #4 card went through some of those version-changes on the 21st/22nd (while it was in Learn), that could also have an impact. Hopefully in light of 1, 2, and 3 not being issues, 4 might not seem quite as concerning to you.
The quirky-step/repeat-a-step issues that come up this way generally work themselves out smoothly when the card gets reviewed again. So that would be the next thing to look for. You’ve got screenshots, so you can check the Card Info for these examples (by cid, Searching - Anki Manual) again in a few days and make sure they are doing okay.