I've run into focus shift with a few older as well as second-string enlarging lenses, not with any of my
apo ones. If this only transpires wide open, you can still get close wise open, then stop down one stop for the final critical focus. No big deal. There some superb camera lenses out there which also have
focus shift with the first stop. They could have easily corrected such designs, but then the max aperture would be smaller. The lens is likely to still be perfectly usable. But if the focus shift is progressive the further you go, you've got a lemon.