I use Dragonflys for travel & don't have that problem. The only difference I could see is the type of needles used. I used PRICK PREMIUM needles. I've heard that putting some vasiline halfway up the need bar works. But I honestly havn't had to do that. Just finished this piece with the Dragonfly's a couple hours ago. I usually use N2's but after hearing of those problems I had to chack it out. I love these machines.
http://amuen.com/Decker/albums/515/16303