Daus,
That happens when you first get a WU. It will take is from 30-120 minutes to settle in and give a good date. Depending on your machine, it's going to be 24 hours to up to 4-5 days.
Systematic, perhaps in your "about" folding post, you can add this one? I see this question asked by all the new folks coming on. Quite discouraging.