In my years of doing nails....ALL kinds of different things factor into lifting, causing "green nails". YES proper application is number one, but I do believe that some people are more "prone" to it. Stress can even effect how one's product adheres to the nail....other things, as you already know, would be wet sweaty palms, is she in alot of water, gardening, medication, ect...list goes on. That's why it's good to keep a record of your clients nails and any reaction they may be having in order to follow up. Maybe she just needs to be primed more than once? Sorry for be so lengthy! LOL
Toodles...........Sassygirl