Did you try "live view," magnified focus? Try it on an object fairly close, with a lot of detail, (live view/magnified.) My first guess was focusing was slightly off. I have an Ai'd 35/f2 and I would not consider it to be a gem on a digital body.
I have also experienced that certain lenses will "jump," when the camera's aperture lever trips the tab on the lens, sometimes blurred, sometimes camera shake. Also give the lens a try on a different camera body & see what happens.
Best Wishes