It seems that we have let closed questions through in places, and you're not really supposed to see closed questions in the app at this stage. The right answer for the time being is that we should be excluding them from the questions list and search results (and the feed, although I think they already are excluded there).
This will be fixed in the next build. This will be fixed soon, but not tonight, probably. This is tricker than it sounds because we have to do the filtering on the client side - the API doesn't expose a way to filter out closed questions. "Well, that sounds easy!" you say, and you're right. What's not as easy is always being sure how many questions you have available to display when the user is scrolling through the questions list.
Edit: just to be clear, implementing all the features it takes to handle closed posts is on the roadmap. It's just not going to come as the fix to this bug report.
Update: the next update should exclude closed questions from the questions list. While we do plan to have more complete support for closed questions in the near-ish future, I consider this to be the fix for this bug. I've now marked it status-completed.