We have a rainshower head as well as a handheld shower attachment in the bathroom. Yesterday after cleaning, the diverter valve of the shower was inadvertently left partially open. When my husband had a shower later, he immediately noticed the pressure from the rainshower head was less that usual but did not realize why. We then noticed water dripping from the ceiling below the shower. It was not a lot and stopped after a few minutes. Today we opened the valve fully, tested the shower and all seemed fine (no leaking below). Could it be this simple or shall we expect further problems?

Expect future problems. Something is leaking but only under certain circumstances. Over the next few days, weeks you may notice what's happening in the home when the dripping starts again. I would remove the handle and escutcheon plate now and reinstall the handle. If you see a leak downstairs check with a flashlight to see if you can see the mixing valve leaking. I suspect the diverter valve. Some valves are water tight fully open or fully closed but can weep when partially closed