|Weird! I have never had anything like that happen to me, and although I tend to use the dryer, I have line-dried as well. Did you use an actual line? Were the diapers folded over themselves or just hung up by the ends? The reason I'm asking is that when I dry on a drying rack (I don't have a clothes line), I always make sure to drape the diapers over two rungs so there's air circulating in the middle of the diaper and in-between two diapers. Maybe if they were folded in two they stayed moist for too long? If not, then I really don't know... I assume they smelled just fine when you put them on the line?