Are some snakes just more picky/sensitive about humidity than others? I have 3 right now, and have had as many as 6 at one time that I kept in identical conditions and this bumblebee male is the only one that has had ongoing shedding issues.
I wouldn't be surprised at all if some individual snakes need higher humidity than others. It probably has something to do with that particular snake's genetics, like maybe the genes responsible for producing the oils are affected. Who knows? You can try bumping the humidity much higher for a couple days from blue till shed, like instead of 70%, go for 90%. And use a digital hygrometer, like the Accurite one from Walmart. Yes, high humidity can cause respiratory issues, but I've only known of it when it's long periods of high humidity.