Not in MMJ growing, but in other plants, I have seen green leaves drop if there is trauma or they are focusing energy/ nutrients in other parts of the plant.
Again, we need detailed info or pictures. You have a handful of people trying to help you, but you are being too cryptic. You will find that people are not going to waste their valuable time if you are unwilling to put in the same effort. Remember, you are the one asking for help. Not being negative, just trying to help you for the future.