Sometimes the wallpaper doesn't respect the On Tap Feedback setting. I had it set to none, but there were vibrations on taps.
If phone vibrates even if KLWP vibration is set to none than vibration is done by something else, your Launcher, the app you are trying to run or something else. If instead you are running KWGT vibration cannot be controlled since its in charge to the launcher currently.
I'm pretty sure it's klwp, because tapping on an empty space doesn't make it vibrate. I'm on oreo, if that helps.
It resolves on its own and returns at random times.
It vibrates even when I tap an empty space. I use Nova launcher. It doesn't have such an option.
Actually the vibration settings are wrongly named (names are swapped). Try setting vibrate light for no vibrations.