I would like to know more details:
What paint? How old was it? Gloss, flat, enamel, lacquer, acrylic?
What reducer (thinner) did you use?
What were the conditions when you sprayed it? (Temperature, relative humidity)
What were the conditions in the intervening time? (Ditto)
What were the conditions when the problem occurred? (Ditto)
Spraying pressure and distance to coated surface?
Exactly what gloves are you wearing?
Some metallics are notoriously fragile. Others wear like…um…iron… (pun intended)
In the case of your last question, only if the paint has gone bad.