Its unclear what you mean.

Likely is: travel together-but then the other one MUST have some kind of NS-season/subscription. Theone who then gets discount-OFF peak only-must have chipcard and load this on card.

Via app only very limited access to personal data-full via mijnNS-open via site.

But in website I am not getting the option for activate

It looks like the options for Samenreiskorting and Klassewissel are gone from the Mijn NS website.

I also see an ad to get NS Flex, even though I already have that.

This must be a bug, it should show the cost counter widget there.

Same here Robert. Plus it is also not possible to check the status of NS Extra (whatever extra's that still gives). 

After problems with invoices, travel history and login problems now this (new?) problem. Getting better all the time NS.

Here something to fix it. 

I'm also having this problem. I assume the conductors have been informed of this problem and won't fine travelers. If they do I want a refund of my subscription for lack of functionality.

Hebben jullie ooit antwoord gehad of een oplossing gevonden? Ik heb hetzelfde probleem.