The Blackfyre Lineage title

Hey not really sure if this is a bug or intended but I thought I'd ask here. I started as a custom character in the Crowned Stag start and adopted the extinct Blackfyre house, in the bloodlines I noticed it grants me a traditional claim on The Blackfyre Lineage titular title, but I can't create it with the option saying "You cannot create a title marked as Inactive". This is my first time playing as a custom Blackfyre character so I don't know whether this is because of that or if there is some special event or condition that gives it to me. Any answers would be welcome, like I said not really a bug as its just a titular title which I don't think does anything, unless I'm wrong, but it'd still be neat to have as now we're the last heirs.