I totally agree with you. You should get a replacement,, that is not defective.
Next time it may fail half way thru the incubation cycle,,,,, meaning the obvious:hit
Just keep doing what you are doing. It is almost at the end. If this is a new incubator, you just purchased,,, I suggest you get a replacement, or your money returned. There is something wrong with it,,, and I would not blame humidity for problem.
WISHING YOU BEST...