About a month ago I replaced my horizontal float toilet fill valve with the vertical style fill valve. It's a Fluidmaster style where the float runs up/down the body of the fill valve. Several times a day I hear water running for about 1-2 seconds refilling the tank. I know it's happening on at least one if not both toilets. I performed a dye test to make sure the flapper wasn't bad and it came back good. I also adjusted the float to the lowest setting as 2/3 of a tank of water has proven to be plenty to flush the toilet. I'm completely puzzled as to why this is happening. Does anyone have any insight as to the cause of this problem?