loosing fan leaves

I am two weeks into flowering and have noticed the lower fan leaves starting to turn brown and crispy but all the new growth looks healthy its just the fan leaves. The temp is fine and i dont think its fert burn cos i flushed well 1 week ago and have not used excess ferts.....is it normal to loose fan leaves during early flowering or should i be worried???:(

normal later in flowering, but a bit early for that. are you sure they're not consuming the leaves due to too little ferts?