If I knew more about your "machine" I might be able to figure out your problem. Al

It is a palstic tub with a pond pump in the bottom that is attached to a series of sprayers. The cuttings sit in a top cover with holes cut out of it, that netted cups fit into. Neoprene tops for the cups hold the cuttings in the center of the cups. Rooting solution is then held in the plastic tub and spayed on to the undersides of the cuttings via the pond pump.

From your description my guess is the fuzzy leaves retain too much of the water sprayed. Do the leaves just collapse? Al

try to change your rooting hormone or the strength of it. i spray the top of the plant when i first stick the cutting then put the dome over it. i put hormone directly on the wound and only deionized water in the cloner-changing that about every two weeks-if it helps

Here is a link that might be useful: rhododendron cuttings

THanks for your help. I think you are right about the leaves retaining too much water. Isn't that the purpose of the "fuzz" on some plants anyway? They just rot in the cloner. I do use distilled water.