sounds to me like it wasnt fully cleaned...happens to paint as well.

if you touch it...the oils form your fingers gets on and doesnt create a good bond between the clear and the VHT. there is a cleaner solution sold at most autoparts stores that cleans the surface completely of all oils. if not use windex...AFTER the nightshades has dried..before the first coat of clear.

this should help out...if not....I have no idea. bad batch of clear?