Our issues may be caused by different things. This is just speculation but I think the cause of our issue was that the page that had the news list had an alternate URL of ~/news and the single item settings for the news list on that page used an autogenerated page based on that main news page, so it assumed those properties, including the alternate URL of ~news. So, when I tried using ~news/2014_24.aspx as an alternate URL on an individual news item there was a conflict. The solution was removing the ~/news from the Alternate URL path in the individual news items because that part of the path was already included in the page properties.
Does your main news page have an alternate URL and is part of that URL replicated in the individual news item's alternate URL?