nope your plant is going to lose leaves here and there it is all normal as the plant is getting to the end of its life, i would start a flush though right now so you will be ready to harvest when the plant is ready. your plant will have leaves turn yellow as no nitrogen, you dont want to use nitrogen when the plant is in flower, reason is you want to focus on bud growth not veg. and leaf growth/ also when you cut the n out you replace it with boosters like 0-50-34, ect,