just saw this thread...
first, this led strip was my first time ever using arduino and leds, so i didnt think much of some issues when they came about, maybe cuz i didnt know what to think, or what to compare it to.
Anyhow, this happened to me also.
First, Im using a teensy 3.0, running 3 meters, but in testing, it was a build up from 4 LEDs to the total 96 LEDs. I was using the example code for LEDbeltKit which slowly got modified as i went.
I had cut every single one of my LEDs into the 2 LED sections, and started wiring up my project. (I needed them all spaced apart much further than they come in the strip.) I noticed this green LED light very slightly upon first testing. thought maybe a bad LED, switched the cut section to another, same thing... it didnt matter what LED it was, it had happened regardless. It was always the first one in the chain. I tried quite a few of the cut sections. I just figured some power was making it to the LED itself when it shouldnt have, but in my project the LEDs are mounted inside a plastic bike frame, and this "glitch" in no way could be noticed through the plastic so i shrugged it off and continued with my project.
Now, I only remember this glitch in the early stages of my project, halfway through i split the data and clock wires to run two separate strips at the same time.
i just opened the frame now and took a look, i dont see this glitch anymore. I dont see it on the first LED of either of the strips. I dont know when this went away and i dont know why.
Unfortunately everything is mounted and i cant try to reproduce this, but i feel this rules out the "maybe the first LED in a reel is bad" kinda thing mentioned earlier.
Also, my wires from the teensy to the first LED were never longer than 6 inches, but currently are about 2 or 3 inches.
Dont know if this helps at all.