Yellow Leaves during flowering.

Up to a point, lower fan leafs are expected to go yellow, as the plant eats up the nitrogen. So yes you should give her some, divided in 2 or 3 waterings, just enough to keep her going for the next couple of weeks, than switch to potassium based. Keep an eye on cal mag and phosphorous and it's all good.

If it’s the fan leaves I wouldn’t worry it’s normal when the are in late flower that’s what I was told

ola amigo tudo bem ? Pelo que vejo parece falta de nitrogénio. Parece que a planta ja devia ter dado alguns avisos disso nas folhas. Mas nada esta perdido, adiciona um pouco mas de N na próxima rega, com ph bem regulado e tudo vai voltar ao normal. algumas folhas podem não se recuperar, mas e normal. Boa sorte no cultivo

If you are in the US or Canada get some Recharge by Real Growers. That stuff helps the soil feed the plant efficiently and makes the leave green AF!

I often have to add some additional nitrogen for the first 3 or 4 weeks of flower above what is included in most "bloom/flower" fertilizer blends.