Yeah, that looks like a nitrogen overdose. Also looks like they're starting to get nutelock, showing other deficiencies. If I were you, I'd give them a good flushing, followed by a 1/2 strength feeding of some veg fert, including the micro nutes. I know veg fert is high in nitrogen, so you might want to go with a bloom fert, for this one feeding, til they recover. Then, switch back, and lighten up a little.