Clones Dead Growth tips?

Hi i have been posting here saying i have been having trouble getting clones to root. Well the answer for me seem to be using 50%perlite and 50% vermiculite. This time i had a much better success rate. Any ways i noticed the ones that did die took root and soon after the growth tip shriveled up, turned brown and died any reason for that. They are under a compact flouro 200 watts that is about 1 foot from the tips?

I clone in dirt, maybe stem root or root rot or nute burn your just using water no nutes right more info would help people humidity temp of clone area ect ect

Its normal for a few leaves to curl up and die on a clone, just give them time and proper care.