if it flakes off in your fingers it's likely burned - it'll even have a "burned" feeling.....if not maybe a k deficiency? heat stress has also done weird unexplainable shit to my leaves before i.e. turning white/losing pigment.
yea my 300watt CFL has done that before when the leaf touched the light for a bit, & it did look pretty much like that, but im not 100% that ur problem
the first thing that came to my mind was it was touching the bulb. i think thats what happened. thanks for the help