I've noticed saltiness on the lips before, most strongly with Bolivars, tubo #2 and belicoso fino both. I read somewhere that it's associated with a strong nicotine content. I couldn't really vouch for that theory though. I've had cigars that seemed to be much stronger in nicotine (Flor Domincana Double Ligero) that had no noticeable saltiness.

The salty Bolis burned just fine though. I don't associate saltiness with a poor burn.

As has already been pointed out, I find over-humidified cigars will burn weirdly.