@rick_templeton -
Based on information in your post, I am assuming that you copied the survey from a previous class into your current class. First question is: how did you create a copy of the survey in the class - using the copy option on assignments? or using the course import content option?
Second, what dates are you referring to? Dates inside the survey questions? Or the assign/due/until dates for the actual survey?
Third - how are students accessing the survey? is it from a link on a page? or is it from the assignment list for the course?
fourth - when you edited the survey question, was it in the survey itself or from the question bank (if that is how surveys work - I don't use them).
Basically somehow the students are seeing the old version, and you are editing a different version that the students are not accessing.
Ron