There are several places to set the title property. The menu item, the category, the article manager and the article itself.
As the other answers have noted, the view and menu item are the most critical to set.
However, if you're linking out of say, a featured article blog view and you want the title hidden when you get to the article page, the menu item may not be acting on the article by the time you reach the full text page. So you want to look at the other areas of settings to see if they're conflicting.
Ultimately, the individual article level should trump all the other views. So it would interest me to test that result and perhaps address it as a glitch in the parameter hierarchy in the Joomla core.