All different strains? Clones? Sometimes you see fucked up genetics that do that but not sure that makes sense unless all of yours are clones of the same mother. Not sure why anyone would clone a mother with fucked up genetics so, again, doesn't seem like genetics.
Stressed out plants can also do that. What sort of nutrients are you running?
I also wonder if running them in sun all day and then switching to CFL is an issue? That's a shot in the dark, I really don't know.
Good luck!