When responding to someone else's comment it is usual on this site to use @ThePersonsName, but often (about half the time?) this does not work. the tab-to-autocomplete label does not appear when typing @ and starting to type the name and after submitting the comment it disappears.
Is this a bug? Does anyone else experience it? Am I doing something wrong?
I'm not sure if this question is appropriate for the meta section, but I couldn't find another place to ask this.
edit: As an example, it didn't work when I replied to this comment with this comment shortly after it was posted (I added @NexTerren at the beginning but it got removed), but it does work now if I try to add another comment there. Could it depend on the time since the original comment was posted?