Also see if the molasses you are using is 'unsulfured'.
I am not sure about the yellowing. I haven't seen that problem.
Yellowing is usually associated with N deficiency- I am almost wondering whether the added carbon is making your plants grow a little faster than normal, making them consume N faster, or if you need to add a bit more to the soil.
I can't help much with this problem- Maybe rhizome will stop by and give a hint.