I have a Pentax DA 35mm lens that was stored in the camera bag for a while.
When trying to use it today, I noticed that the focus ring motion is not smooth. It is "snapping" at specific intervals, 3 times for the full ring travel. Smooth motion when starting rotation, then offers some resistance, then smooth again, resistance again, smooth until it stops.
It seems this happens when the focus thread (in the rear) is oriented the same way. There were some tiny liquid droplets on the rear of the lens.
The lens seems to work well otherwise, but I worry the effect this will have on the camera auto-focus mechanism.
My questions are why this may have happened, and how to fix it?