I think Porfolio is not referring to Typekit subscription but to Adobe portfolio and the typekit plan is the free plan on student version .
To be sure ,you can sign in on this plan page and you'll see which plan is included in your subscription :
Most paid Creative Cloud subscriptions come with a Portfolio Plan on Typekit as you mentioned. However, there are exceptions. This document explains a bit more about this: System and subscription requirements for Adobe Typekit fonts.
I hope that helps explain. If this still seems to be an error, drop us an email here: firstname.lastname@example.org, with your account email address, and we'll look into it.