I've had multiple projects go this way, where I'll start them, be interested in them for a bit, then I'll go 'something's missing' and start over? Reach a similar point, attempt again, but something just isn't working. It happens very rarely, where I'm like 'this idea is cool' but like, I have nowhere to GO with the idea, if that makes sense? So like, I'll have an incomplete picture, and start writing. Sometimes I work on it and actually finish it, but something feels 'off' like 'imperfect' so I try again, and hope it works. There's this particular idea I've been toying with, and attempted to write a few times. It's kind of a darker take on Who Framed Roger Rabbit. I've tried so many times (at least three times) to START this thing, but whenever I do? The ideas just, stop. And then I don't feel like working on that project anymore. (unlike a different project where I'm determined to push through and finish it even if I am on my second draft) If I had to guess, it's just my internal editor being a jackass and not letting me be happy with what I have. But sometimes it feels like something else is off/unpolished about the idea too.
Believe Me I want to work on this thing haha every few months it taunts me with some new version. It's just, I have the seed of a story, but no actual you know, plot. If that makes sense? I'm also juggling like two other projects as well. I need to focus down Hound and Fox and get at least the second draft finished.
If it happens very rarely for you, it's not a big deal. Artists usually have a few projects that don't quite work, and they are usually cannibalized or significantly reworked later, or even just binned in the end (Or binned, then released in their partial form by your spouse after you die a famous writer). If it does bother you, then try a different approach instead of repeating the same one. Force yourself to complete the 'picture' before you start writing, for example. Planning a project is a great way to uncover deep flaws that try to hide behind the mask of 'writer's block.'
My internal editor is like a disapproving movie-of-the-week father. Nothing I do is good enough for him. None of the first chapters I've written for a potential third book have made the cut. Problem is that at the current course I keep winding up at the "nope, this is just Mad Max again" point. Not that starting an entirely new-new project fares any better, but there's this quote I don't know the origins of: "There is no failure except in no longer trying." What can you do? It's got quotation marks and everything. All the most profound stuff comes in quotation marks.
I've probably posted something similar about this on other threads, but I feel like the best way to get words down is to turn off your inner critic and just write. I'm not a planner - I have a notepad of ideas and I will know of a handful of major plot points that I will want to hit in the story. I focus on getting from one to the next, and I try not to overthink things. If I ever get truly stuck, I will start editing what I've got down already from the beginning, which gives me a good feel for what should or could come next.