Sometimes there are things that your body just will not do, we all have different hands for example.
I had a similar post a few years ago.
My fretting pinkie wants to curl inward and almost under my ring finger.
No amount of practice will correct this.
I am not sure if this link is correct but there is a medical condition similar to what you describe.
Like anything else this condition can exist in many different levels.
https://en.wikipedia.org/wiki/Clinodactyly