Sometimes the system experiences a delay in updating app lists. This can be due to many reasons. For example, Microsoft might take a while to verify an app, or the app might have been hidden when it was uploaded to the store. We advise developers to submit their apps 48 hours in advance to hedge against delays.
We just did a manual update and this app is now showing up; however since the deadline has now passed it is too late to submit it. We apologize and hope that Lee is able to participate in future Challenges.