Most likely too much pottassium and it lock out nitrogen.
Normally, I don't switch immediately. I mix half vegging fertilizer and half bloom fertilizer.
You can solve this problem by flushing. After this, use only 1/4 strenght of bloom nutes and step up. This particular strain might eat less than what the fertilizer manufacturer say how much to use.
Buenas! Parece Clorosis Ferrica, , puede ser o bien por un ph inadecuado a la hora de regar, Necesitaria saber, que abonos le estas hechando, con que frecuencia de riego le das, a que pH lo ajustas etc...
Espero tu respuesta!