I had a similar problem about a month ago. I'm growing in a basement with soil, suddenly everyone started getting sporadic pale white spots (actually on the leaf, not eggs or mildew) and turning yellow. Stopped using my humidifier, trimmed off ALL my sick looking leaves, and rotated wipe-out, safer 3 in 1, and some stuff called 70% neem that had a fungicide and insecticide mixed in. Let my humidity get down to 50%. I also started testing my run off with a $20 kit that checks soil PH, nitrogen, phosphorus, and potassium... all of them were off. I also had this weird thing with there still being a couple of flies in the house (upon a closer look, they fungus flies instead of common house flies). There's a condition called spephia? that is bacterial or fungal and causes yellowing. I think it was a triple threat of insects, fungus, and poor nutrition that caused the problem. I tossed a tray of rooted clones that had turned yellow, dropped the humidity, re-balanced my nutrients, and now use maintenance sprayings for pests and disease. It's been a couple of weeks, but everyone seems to be recovering.