Olight tailcap defect

I recently got a M20 which was dead on arrival and it turns out it was the tail cap. It wouldn't turn on at all with that tailcap, but it would if I shorted the batteries to the body or with my M21 tailcap. Tightening the inner aluminum part didn't do anything, nor did cleaning the contacts.

So I took apart the tailcap and found the threaded aluminum part was machined too short which allowed the plastic insert to stick out too much. This prevented electrical contact with the PCB board on which the actual switch is mounted. See the photos below showing the difference between a good tailcap and a bad tailcap.





It's a defect, it happens. I ended up filing the plastic insert shorter to match the aluminum height. If you have problems with your tailcap, you might want to check this.

robinhood4x4, good infos. I once had an issue with the M20 rubber boot, it makes a "double-clicking" sound when trying to click on, feels annoyed as it gives a texture feedback to my thumb. Turns out this "double-clicking" sound is result of the switch sliding off the protruded rubber pad inside the boot when press at certain angle. Changing to a Fenix rubber boot fix the problem.