Thanks for the suggestion, I shall try, but like I said, it affects the manual focus too, so it can't merely be a dirty contact issue. The original problem was on a K-5, but this last incident was with my K-5 IIs, so it's not even a camera body issue either!
By focus lever, do you mean, the MF/AF switch?
---------- Post added Jul 4th, 2015 at 10:51 ----------
Quote: Just to be sure we are talking about the same lens, there is no 'macro' setting on the 18-135? Perhaps you mean minimum focus?
Yes, minimum focus. I think macro, because even though it's not called a macro, it is really quite a nice little macro lens for butterflies, etc.
I tried switching the MF/AF switch, but it didn't seem to help any. Usually when that happens, the lens was focused quite far away already, so I don't really remember of hearing the lens trying to focus. Autofocus works just fine, it's just out toward infinity when the focus acts up, whether AF or MF.