Im no expert but I think it has something to do with the humidity. Try putting a clear bag or dome over them for a couple of days when putting them out, it might help.
Sorry for the late reply but I wouldnt worry about it too much cause my vegging plants where growing right into the light with no noticeable negative affects, I think you should be fine.
Im running that exact light in my closet which is 4 feet long by 2 feet wide. I keep mine around a foot and a half away from the canopy. Only been vegging with it for a month and half but so far they look great. Hope that helps Oh yea and since using this light I haven't noticed any jump in my...