On enwiki and testwiki additional restrictions for creating pages in (main) namespace were added somewhat recently (see also T204016). This access was added to the site configuration for "autoconfirmed" but not the "confirmed" usergroups. The primary purpose of the "confirmed" usergroup is to allow for manually granting access that autoconfirmed has, so this appears to be an oversight.
Short hold for comments is open at: https://en.wikipedia.org/wiki/Wikipedia_talk:Requests_for_permissions#%22confirmed%22_users_can_no_longer_create_articles