Yes, if the subject/title is a question as well. There are a very large number of questions with titles that are not questions (highly voted example here). It just wouldn't make sense to stick a question mark at the end of that.
In the two edits you've linked, the titles are not questions, so they should not end with question marks.
Strictly they should to keep to normal written English style. However I think that leaving them off on this site in a title is ok.
Either way editing just to remove or add the '?' is just not enough. If the edit was reviewed I would mark it as too minor (but then I see many edits approved where I have said it was too minor).
It's an issue of style more than anything. Certainly, if you can express your issue in a succinct question that other users can view via the title, it's preferred. Having an identifiable title will help your question get attention on the front page, where there is no other description besides the tags.
However, if this is not possible, a descriptive summary of the subject/issue at hand works just as well. Remember, in the
Questions tab, users can see N of the first characters of the question anyway.