I think the light when it hits the roots some kind of vitamin in it maybe reacts with the structure of the roots and kills them off thus turning them brown, or may injure them and then they can be weak and rot inside the soil.. never take chances, dont loose those beautiful plants there

Ive heard also about that thing to speed up flowering..
supposebly you do 11h on 13h off with the lighting schedule and it makes flower finish a little faster but on the long run it will reduce your yield and also not mature buds in the correct way. the plants are living beings we must not forget that although fast they grow some stages are a little time consuming..