It seems every cutting I try to grow, when in the cup [mostly perlite with a small amount of compost] and covered with a clear plastic covering either turns brown and the end and drops leaves. If leave the humidity covering off, of course they will dry out. Just trying to figure out what's going on, before these cuttings are done for.

Maybe a happy medium, cover on, but off a few hours a day, or maybe some small air holes. Fresh air is important, just like humidity.

I think one of the benefits of the plastic bag is that you can bury 90-95% of the cutting, which eliminates the moisture loss from the cuttings, and allows greater quantities of fresh air, thus eliminating mold and other issues. Unwashed, untreated, unbleached, un-anything cuttings are 99.9% mold free. I have none that have dried out, and the ones I am losing have been from excessive moisture, only. Enough humidity and the moisture in the rooting mix around the the cutting seem able to support the water needs of almost unlimited top growth, even without roots. The moisture/fresh air balance is much, much less of a factor when almost all of the cutting is buried.