mine has done the same thing, leaking injectors is an idea cause it will backfire (atleast once everytime out) when i go to start it. will be watchin this post.
My '09 M8 HCR does the same thing. This is my 5th Arctic Cat EFI and I always let mine idle down before hitting the kill switch. So that isn't it.
Mine only has 180 miles on it and it happens out of the blue. After taking a break it will just not start. It is like the kill switch is off. I turn off the key then back on. Turn off the kill switch and then back on. Try again. Still won't start. Pull 10-20 times. Nothing! I get tired and wait 30 seconds and then it just fires up and runs perfect. Just like nothing ever happened.