By default, in which cases QuestyCaptcha asks question while editing/adding an articles and when not asks? Does it depend on email confirmation?
Topic on Extension talk:ConfirmEdit
Defaults for ConfirmEdit are listed on its page; QuestyCaptcha uses these defaults. In particular, captchas are by default shown to everyone except for bots and admins, any time a new URL is added to a page, an account is being created, or a login fails. See the section I linked for details on how to customize this setup for your wiki.