yeah its environmental shock... when they are in a humidity dome they take in water from not only the small amount of roots but also the leaves, thats why a lot of people will snip their leaves in half, cutting the tips off leaving a large opening, which actually does 2 things, slightly stunts leaf growth and opens up more surface area to take in water as long as the humidity is not low, after a week the leaves will have healed and there should be roots, but after relying mostly on foliar absorption of it takes a while for the cutting to adjust to root intake as opposed to foliar... so as said above you need to gradually introduce them to the rooms ambient humidity... otherwise they will go into shock, droop over and take a while to adjust, this hurts the plant, so easing it little by little allows it to naturally adjust without shocking the cutting... but thats not to say that MJ isnt a resilient plant, in all honesty it can take quite a beating and still turn out fine, as long as it isnt too often or for too long...