Leaf discoloration can only be determined by the grower. Over watering can look like and nute deficiency or overdose. Leaves start to die the last few weeks of flower. If u are flowering a sativa dominant, u can get leaf discoloration 4 weeks in. Be patient. I have asked people to look at my pictures and I will get 20 different opinions. U have to retrace ur steps, if u did nothing wrong then it is natural. I am in my last 2 weeks and my leafs are turning yellow and I am Indica strong. Also, I have been flushing the last week too. I am using FlolaKleen. Leaves have 2 weeks of nutes in them. I hope all my leaves are yellow at the end!!!