Netflex Shared Membership won't work on Netflix app

Hello All,

I have a family member who has a Netflix account (not linked with Xfinity).  They purchased a Shared Membership and added my Comcast.net account as the address.  I went through the activation process and was able to sign into Netflix via my web browser and everything looks correct.  However as soon as I attempt to sign into the Netflix app via my set top box it prompts me to pick 1 of 3 plans and it looks like it wants to start charging my Xfinity account.  If I cancel out of it and go back to my family members main account the shared account is removed.

I have tried this twice now, once with my Comcast.net account and another time with my Gmail account.  I have to wait for their next billing cycle to try again, but next time I am going to try to sign into a Netflix app on my Roku instead of the set top box.

Does the Netflix app on the Xfinity set top box use a different sign process for Shared Membership Accounts?

Has anyone else run into this?

Thanks,

Ian...