It's probably just that you're so used to chicken scratching that it's become ingrained as a habit. Habits take time to break, keep resisting the urge and overtime you'll feel it less and less.

When you say chicken scratch, do you mean that you are trying to "find the line"? This is what I do all the time too. Ghosting the line first and thinking of drawing from the shoulder does help me though. LIke Somethingx said, I think it is a habit that takes time to break and reform. I would also agree with Aturia24 that when you are doing the 50% rule, it's not practice so you shouldn't beat yourself up if you do it. I am finding that the habits I am trying form with DAB such as line quality and dimesional thinking are slowing seeping into my 50% fun. It just takes time.

If it's a personal project, chicken scratch all you want, that's the point of the 50% rule :). The idea is that if you commit yourself to the drawabox lessons, you'll gain a more instinctual understanding of it's principles. When you go back to drawing for fun, those principles will slowly unwillingly present themselves in your drawing. I used to draw from the wrist all the time. Now I instinctually draw from the shoulder more, without consciously trying to because it's simply cleaner and more accurate (for larger subjects).

I think it's good that you leave mistakes as they are. It's a more accurate representation of your skill level, which is important for other critiquers to point out.

my lines have notably gotten cleaner when they arent chicken scratched or redrawn so im not sure how to deal with this problem

Well if your lines are improving, then why resort back to chicken scratching? Is it because it feels familiar? For the 50% rule you can let go, but do keep practicing drawing from the shoulder with clean confident lines and I'm sure at some point that will feel more familiar than chicken scratching.