shargrol:
Practice is never linear. We go up and down the nanas and the vipassina jhanas. Sometimes even up and down many times during a single sit. This is totally normal and not a failing of the practice if it happens. It's common, especially off retreat.
You can basically assume that each sit starts at mind and body and then will quickly move to whatever the mind knows needs working on. And then from there might go up or might go back down and "refine" lower nanas -- it's important to trust that the mind knows where to go.
Sometimes people worry about "falling back into the dark night nanas" -- but this fear simply shows that the person really hasn't understood the lessons that the dark night teaches (that fear is just fear, misery is just misery, desiring deliverance is just desiring deliverance, etc.).
Often, when someone is starting to develop clarity of mind and clues into their psychology, the mind will take the meditator into the dark night nanas so that they can use this new clarity of mind to have insights into stuff that was missed the previous times through.
It's really interesting the way the mind works.
Wow this comment is saving me alot of unneeded grief from trying to game the system. I have been thinking that I need to change up my practice while in the Equanimity nana to keep pushing to stream-entry, treating meditation like going to the gym or a race, but my mind needs time to work through the things it needs to work through, and that's ok. Thanks for the thread Kelly, and for this answer Shargrol.