You don't say old your lens is but in general, lenses can become internally misaligned with age and use.
(I think this is more of a problem with the wider angle lenses.)
Never could afford the 24/2 but I did have an old (about a 1980 model) 24/2.8 that made pictures about like your example.
A trip to the shop for a CLA and re-alignment on the Nikon collimating (SP) jig and the world was all in focus again.