I did a mission with the Reaper indoctrination machine and the husks, and after the mission my level 30 soldier reverted to the default face, armor, and turned into a level 1.
Edit: Squad points were also reverted to 0, all abilities at 0
Yeah, just did that. Lost only about 20 minutes, but since it actually stayed and going to the citadel and stuff didn't fix it, I was disturbed for a bit.