It cannot be gold you do not need to be a master grower to know that,in fact you do not even need to know anything about growing to know that.Looks like fake news to me.If it is really happening you will need for someone who has experienced the same thing and actually identified it.Not an opinion of what it could have been, but actually was.Ask( does anyone else have access to my plants could be a prank)?What am I using on these I have never used before?Are you spraying the plants with anything?Now for the big question.is that the actual color or is that just the color it turns into after a few hours?does it attach itself to the plant over time or still wipe off?is it there in the morning does it happen over night?did something drop from my bottle or something on the leaf?Ah so many questions and not enough answers.If by some miracle it turns out to be gold I would like some of the seeds LOL.Seriously best of luck to you,don't let it drive you crazy trying to figure out.unless its to late and your all ready crazy like me.Very unlikely all other possibilities have been ruled out there endless.OH just a thought,its hard to tell from pictures but looks like sodium crystals turned gold color,or the hard stuff that develops on the neck of a bottle of liquid when exposed to oxygen and is kind of sticky and drops off when your stoned and don't wipe it off first or gets on your sleeve or something you touch.it certainly is baffling.