hey there,i've done some research and maybe you got some deficiencies going on there,in my opinion ,you should look at this table https://www.alchimiaweb.com/blogen/wp-content/uploads/2015/12/KRuFnY4-1022x1024.jpg ,if your leaf has some strech marks ,wormlike brownings on the leafs then maybe its some sort of bug wich eats the plant from the inside of the leaf,but that's hard to develop there(LEAF MINERS),it looks like a cal-mag deficiency in the late stage but it's a bit tricky becoz even potasium late stage deficiency can lead to those sort of markings,but for sure that's not a heavy nute burn to be honest ,check here --- http://www.ilovegrowingmarijuana.com/nutrient-burn-in-marijuana-plants/ ,hope this helps you clear out the problem :D i would bet to add some cal-mag trough the process and reduce the bloom nute a bit just in case,4ml is more than enough ,happy growing!!