joining multiple protected content memberships

I have created a couple memberships for protected content and was testing to see if a member could register for more than one protected content memberships and it seems that when trying to register for the second protected content membership it does not give you the option to compete the payment or registration

I am seeing the following message
Please check the details of the membership below and click on the relevant button to complete the signup.

their is no relevant button to complete the signup
FYI both memberships are free please advise?