Out on a field trip today and my X-Pro1 would not allow a shutter speed slower than 1/4 second while operating in aperture priority. I was attempting to "blur" water motion, which I have done previously, using a 4-stop ND filter and small aperture to get to a shutter speed of about 1 second, but the camera "bottomed out" at a speed of 1/4 second. (I was in aperture priority, ISO=200, f/22 on a XF 55-200mm lens). Slower shutter speeds could be set in shutter priority, so I was able to accomplish my photographic goal, but there appears to be a problem or a setting that I apparently changed unknowingly that prevents slower shutter speeds. The camera firmware is 3.20 and the lens is 1.11; both are current. Anyone have any similar experience or an answer for how to correct this problem?