Hello gen.

Yes I find that disease is quite oftenly found, so not new.

I was growing 3 plants, lights were about 3-4inch from tops. Yes each of my 3 plants were different sizes only because we cloned the biggest one twice @ different times.
I did have one night when I started flowering that they grew alot and i didnt notice them touching the bulb and yes they burnt a little bit. Each ballast I had was 60w.