A disclaimer: I don’t have the non-beta version of C8 and I don’t have the beta version, so take what I’m going to say for what it’s worth, and hope somebody more knowledgeable can give you a definitive answer.
If I’ve been understanding issues people have had, you’ll have to re-install the 8.x non-beta content. From what I gather, you need to be careful not to install over your non-beta version, but rather save it in a different directory. If you don’t have the installers archived locally, you’ll need to download them from DAZ all over again. Try resetting your downloads.