So I had a moan on twitter about this issue. Kinda blamed Window's and unexpectedly heard back from the account you'll see below.
http://i14.photobucket.com/albums/a350/juggalo_zero/forum%20stuff/Screenshot_2016-01-27-00-06-27_zpsab6hiy6y.png
http://i14.photobucket.com/albums/a350/juggalo_zero/forum%20stuff/Screenshot_2016-01-27-00-06-41_zps5p5sgqj0.png
http://i14.photobucket.com/albums/a350/juggalo_zero/forum%20stuff/Screenshot_2016-01-27-00-06-46_zpsafar3mn2.png
It's quite odd, I randomly lost a skill on my Gunslinger too :/. Had Armstech, Investigation and Scavenging but investigation went missing and I had to learn it again.
Just thought I'd show off my leetness in crew skills, I can haz 4!!!
http://s14.photobucket.com/albums/a350/juggalo_zero/?action=view¤t=Screenshot_2011-12-24_21_41_35_459093.jpg