Well Monk I have had a few do the same thing. I never worried about it. The only mold on a cigar have ever seen looked like the stuff came from another planet, kinda like the stuff in your fridge looked when you got back. My rule is - If it brushes off its okay. Maybe the airplane ride, high altitude and cold, caused some funky kind of bloom. Maybe some of these other guys have had this experience when traveling with boxed sticks before? I usually find Gurkhas are a little on the wet side when I buy them so I put them in my Humi for a week or so (in the cello) to dry down to the 65% that I like my sticks.
Gene