I would defer to Weezard every time, but I'll give you my best take. Based entirely on what you have said, I can't see how this could be simply related to this recent watering schedule. From the photos it appears at first glance to be nitrogen toxicity, which results from severe over-feeding with High N fertilizer, especially over a period of time. But the bronzy scarring developing in the spaces between veins looks like either some kind of nutrient deficiency, another form of toxicity, or mite damage. You claim no mites, so I'm going with a real fundamental screw-up in nutrient availability. Erratic watering can cause stress, but this seems like more than that. I would avoid doing anything drastic right away. You don't want to compound the problem by adding another stress if you don't know if you're addressing the correct problem. Running clean water through them for the next few waterings sure can't hurt, and it may help flush out whatever imbalance may be present. Think carefully about how you mix up your mater/nutes. Is it possible you are formulating improperly? Are you feeding on successive waterings rather than alternating with plain water?

In my experience with indoor horticulture, the main source of problems for people stem from either over-watering, erratic conditions, or over-feeding. I find that in the Cannabis growing community there is a near religious zeal to feed, feed, feed. Plants are damn good at utilizing the nutes in the medium, even when it's not ideal. I always err on the side of less fertilizer, especially nitrogen. If your water and soil are out of the 5.5-7 range you will develop things like this also. Its a pain but you need to monitor those things CONTINUOUSLY. As Weezard says, you're a great grower until something goes wrong, then you're only as good as the records you keep, because that's the only way you can solve the puzzle accurately. There are many many variables at work so the more you can account for, the better. Post more pics of the leaves if you can. I'd like to see more examples. Don't worry, we'll figure it out.:jointsmile: