Hey folks!
Just wanted to chime in here and throw out a few bits of info. It looks like the advice here was good:
Burn in times are very important, it certainly could cause strange behavior if not done.
On an ATI fixture, be sure the label end of the bulb is at the vent end of the fixture (end with the cord). This places the most cooling on the most critical portion of the bulb.
Preserve the life of your fixture (fans in particular) by regularly blowing out salt creep. Using compressed air blow out the fan, just be sure and hold it to prevent it from over spinning. Wipe down the fixture regularly as well.
Controller failures are very rare, but if you do have one we have the parts available for warranty or non warranty repair. A video is available on youtube to walk you through the fix.
Dimming T5's is a bit of an organic adventure. Not every T5 acts the same. Some will go down into single digits of intensity, others will quit at 15-20%. Most won't fire at a very low intensity but will operate down to that intensity once fired. This is likely the situation of the OP. It wasn't stated what intensity this was happening, but it was likely right at the window of when the bulb would ignite, twisting it caused just enough of a change to spark ignition on the bulb. I would guess this occurred during a less than 20% setting. If not, I am not sure what would have caused it.
In older fixtures this can occur due to corrosion on the end caps, twisting the bulbs makes just enough better contact to cause the lamp to fire.
