Occasionally I too had fits using the Kick in my PrecisePluses but things have settled down.
I don't know exactly how you have your 18500 set up, so if you haven't already watch
The Kick by Evolv: Kicking the PrecisePlus from Super-T Manufacturing - YouTube . The exact setup that David demonstrates works the best for me - one thin o-ring under the battery, one #12 o-ring around the top cap, and I use one switch washer. Make sure the switch post & washer is good and tight, and make sure the spring is clean and seated well on the switch assembly.
The Kick seems to like things very clean. See that the Kick's top and bottom contacts are free from dirt/corrosion, wipe off your P+'s contacts with a soft clean cloth, and also check that both the positive and negative terminals of your batteries are clean.
Once I got things sorted out my 18500 has been performing great with the Kick, but I was sure irritated at first.
Good luck.