Hi, I really need somebody's help!

I did some cuttings earlier in the summer, and later, and I had them root good. I was very happy! I took the bottles off and a little at a time I took them out on the backyard table, which gets only some morning sun. They were all rooted ( I finger digged up to finding the little root ball, and seemed fine.

but they are getting the tips black as if drying, even if they are mulched in their pots and moist. All are short cuttings about 3-5 inch long. I cut off the black tips, and they blackened again, swalowing the leaf bud. Continue to black to the ground. Some still have some green stem, some almost do not. Many don't have a leaf bud anymore...

Will the roots sprout a new stem? or did I lose them? What can I do for the ones that are still green? if I cut, the die-back comes back and advances down the stem....

Please help

Thank you