Focus and parallax adjustment is not the same thing. Your sight picture could be 100% in focus while having parallax or vice versa.
I had a nightforce scope that had the focus and parallax slightly out of sync with each other.
I could focus the image as sharp as can be and then I would have to roll the parallax adjustment about 3 degrees counterclockwise to eliminate all parallax.
It was very consistent and I learned that with that specific scope, I focused it, then went counterclockwise until the image just started to go soft and that was right where my parallax error was at it's lowest.
I now teach people NOT to focus their scopes, but to adjust them for minimum parallax error.