Not true. 50%-60% humidity during shed is just fine. Especially if the average humidity is stable in the 50% range all the time.
To the OP...I'm not sure what's going on with your snake. It's hard to tell anything by your description. Sometimes they will get little patches of gray or off-colored scales that are normal and harmless...but what you're describing sounds different than that.
Pictures would help, if you can get some clear, detailed pics. And a full description of your set-up might help us diagnose husbandry issues for you.