On group pages, when the user cannot join more groups due to not having a Premium subscription, the message “Upgrade to Builders Club to join more groups.” appears.
Now that premium is out and BC is gone (to buy) I’d expect it to say instead: “Upgrade to Premium to join more groups”.
This happens as far as I am aware on Phone and PC. This isn’t OS specific.
The bug occurs always, regardless of when or what group you try to join as a non-Premium member. This eventually will confuse players as there is no such thing as BC anymore.