No dynamic values appearing when connecting Flow to a Group Form

I've a basic Group form and when it is submitted I want to use Flow to compose an email using values from the form. However, when I follow this tip - https://techcommunity.microsoft.com/t5/Office-365/Flow-does-not-connect-to-Group-Forms/m-p/295047 - and use my Group form ID in the Flow, no options for dynamic values appear. Is that the expected behavior?