Checked. Plugin settings only allow questions to be enabled for all categories or just some of them, not make them default or not.
Yes, still I think this is a intentional feature, not a bug... And I love this thing of automatically asking topics as a question in the categories selected, and not like a normal topic, because sometimes users don't know how to do it, or even don't know if the forum has that plugin or not.
Also I notice that categories not ticked on plugin settings still have the dropdown button showing on composer area with "undefined" instead of "question".
This is definitely a bug... Should be nothing on the arrow dropdown menu on the non-checked categories and you shouldn't be able to ask a question or mark topic as a question in that categories.
I already reported this on plugin repo a few days ago, but I still have no answer: