Google N toxicity glossy leaves i was getting curling and waxy leaves thats early sign of over feeding N im using floranova bloom and havent fed straight water for a week plus N toxicity slows down bud development in flower IMO
I tend to think of N toxicity as an NPK ratio too high in N. Overfeeding can result in symptoms of N toxicity (I've seen it myself). But, the primary cause is overfeeding, not that there is too much N in the nutrient solution. I.e., if the nutrient solution is weakened, the N toxicity disappears (with the next plant at least).
In your picture I don't even see the blackish green nor distinctive claw. All I see is gloss. So.... I'd say overfeeding.
If you continue as is and measure your runoff PPMs you'll probably see them rise as salt builds up in the soil. In early flower you'll see nute lockout. If it's overfeeding, I'd feed water only the next watering, then feed 1/2 what you feed (being prepared to move up to 2/3). You might also feed with more runoff to help push out unused nutes. This could let you feed stronger with less risk of overfeeding.
