For metered content, "non-members get a select number of free stories in their member preview, which replenishes on the first of each month." (see https://help.medium.com/hc/en-us/articles/360017581433-About...).
If you hit the preview limit, you get the message "Not every story on Medium is free, like this one. Become a member to get unlimited access and support the voices you want to hear more from."
Non-metered (i.e. free) content is not behind the metered paywall. Also if the author posts a "friend link" the article is freely accessible, even if metered otherwise.
Do you have other sources?