Piston thinks it's powered when it's really not powered at all

so I was creating a simple 2x2 piston door, I finished, and then I tested it out. I clicked the lever and my finger was pressing on the right button for a little too long and the lever went on-off-on in a very little amount of time. the pistons freaked out and the top one pused out a block , but not the bottom. i turned the lever off, but the pistons were still extended. I tried the same fast-click lever thing, and it happened again. I suspect that it was becuase they were powered on and off rapidly. I included a couple screensots.