Why isn't the Associate Button appearing?
In our Portal, we have an advanced form where users can fill out their certifications. To accomplish this, I add a second tab to a form on Contact Table, and add a subgrid for the certifications. This tab gets its own Advanced Form Step. I add metadata to the step, and specify the Associate Action as shown in the screenshot.
In the resulting portal page, I can see the list of certifications (if there are any), but there is no Associate Button. Just to check, I added a Download Action. That button appears fine.
For testing, I have added all table permissions with Access Type Contact to the Certifications table.