I recently (2 months) replaced both fill and flush valves in 2 toilets with Fluidmaster products. A week ago I noticed both toilets fill valves are turning on even though the water level in the tank is at the full mark. (Note: the water level at the full mark is below the overflow tube.) The fill valve runs for about 10 seconds before turning off. I did a test where I slghtly lifted the flapper allowing water to leak slowly into the bowl and found I had to allow the water level in the tank to drop at least 1.5" before the fill valve turned on. Therefore, this does not seem to be a problem with leaking around the flapper but a fill valve problem. Any ideas of additional adjustments I need to check/make? Thanks!