If it is not insect damage, then...
It might be that your plants are losing water, and the water droplets are forming on the edges of the leaves in the early morning before lights on...and when your lights turn on, they are burning the holes in your leaves.
Are your humidity levels above 80 percent?... and your temps above 84?... if so, that may be your issue.
It's a possibility... If all else fails, check them before lights go on and see if it looks like you have morning dew on your leaves.