ya I have fresh air coming in on both sides of the room and run CO2 off a tank with a regulator. My lights are vented from outside air then go back outside on the other side. This is not a first grow in the room, there are other plants that are just fine and vigorous all around this one. This randomly happend to one in veg like a month ago and I have never seen this problem in 3 years. It is almost like the roots completly stopped uptaking anything, like a clone where it only absorbs moisture into the leaves from the high humidity because of no root system, yet it has a root ball the size of a basketball that is very health looking. I also soaked in H2O2 to try and help rid anything bad on the roots.