I think you have the same problem I do, I posted about mine with pics and they have the same goldish spotting, a few people said its probably a calcium deficiency and I've also done some research and found that calcium/magnesium deficiency go hand in hand, my advice would be to get some cal/mag. That's what I'm doing. My thread is called "leaf problem/ can't diagnose" it should be on the first or second page, check it out and tell me what you think.
I had something that looked just like that. I determined it was a calcium deficiency caused by the high acidity of Roots Organic soil I was using. There's alot of peat in there, if you don't amend with dolomite lime to keep the acidity in check then Ca will get locked out, most of the time along with Mg. Add to that I was using RO water using only 5ml/gal of CalMag.