Do some searching on the L1P switch. I think there might be some history there. Perhaps 4sevens can chime in. Anyway, I seem to recall there was once a yellow switch, and then it got replaced with a red switch. Or maybe the other way around. Regardless, the new switch is more reliable than the old.
I'm also of the opinion that the new switch is a fraction of an inch longer than the old. I've bought two L1P lights. My older one tail stands pretty well. My newer one was just a bit wobbly, as the rubber switch boot sticks out just a bit when the light is on. It would also turn momentary off with just a feather light touch.
I believe I fixed both problems. I took an old Sanyo CR123A cells, and cut off the wrapper. At the negative end, there is a little translucent white plastic ring. I believe Surefire cells also have a suitable plastic ring. Battery Station branded cells do not have a usuable plastic ring. After obtaining a ring, I unscrewed the tail switch from the inside using a pair of long needle nose pliers. I pushed out the switch's innards, and reassembled everything with my plastic ring between the rubber boot and the switch body. This effectively keeps the switch body just a little farther away from the boot, allowing it to tail stand properly. It also keeps the tension of the rubber off the switch mechanism when the light is on.
I was inspired by threads discussing the use of a plastic spacer to improve the action of the Surefire Z57 switch assembly. Although the construction of the Fenix tailswitch is nothing like the Surefire, the concept of the spacer seemed useful to me. I don't know how this might affect the waterproofness of the L1P, so I'd recommend keeping it away from water if you're going to try this modification.