Are your beads totally saturated? They would look all clear, without any white. What kind of cigars, or do you have a variety of cigars? If you have all one kind, maybe they have construction issues.

I can't see where the position of the hygrometer IN the humidor makes any difference.

When you smoke the cigar, is the draw very hard, like it's plugged? Does the ash look especially dark / charcoal colored insted of more white? This could indicate too dry.

From what I read, my money is on poorly constructed cigars, not the humidor. Just my analysis.