I'm getting a "Page Not Found" error when viewing the children pages of one specific parent page. The parent page works, but not it's children. If I change the children to a different parent, they work. I don't think it's a permalinks format issue because they work under different parents. There are no weird things about the parent page that would cause this. I believe it started happening when I briefly moved a child page up one level and then moved it back under this parent, but am not 100% sure it that's the change that caused it.