hi , most plants ive grown have yellowed large fan leaves from about halfway through flowering till end somtimes the leaves just fall of, but it might also be a problem , the way i look at it is if my plants are growing and tacking on feed then there usually ok
. so if your plant is still growing and tacking on feeds as normal . i would say its ok and normal for strain to loose fan leaves, just personal opionion
maybe some else can help more
maybe post a pic or 2 that would help
clem the bob of 101