I have a hunch it was something else or just an anomaly. I'm a big fan of Mars and use two of their lights, but that light is a 134w draw. You should be able to get that something like 6" from a mature plant without any adverse effects, as long as heat isn't an issue. At 18" away, it's only 387 uMols directly under that light. They can take a lot more than that! The Reflector 144's I use are 873 umols at 18" under the light.
That is a great veg light and, as with a new seedlings/clones, I'd start the light high and lower it as you see no signs of stress. As a flower light, again, if heat isn't an issue, it can literally be less than a foot from the plant and that 6" number I tossed out earlier is probably pretty accurate!
During the feeding tomorrow I will adjust the ties make sure everything is ready for the stretch and then let them go!
like hot cakes in a pancake house!