The new fact that each requires a road connection is a terrible and pointless decision that I suspect is more about lazy programming than actual intent.
The Wiki Set Building entry of Dec. 4 says:
Any building of a set can serve as a Portal/Connector for the other buildings that are part of the same set [emphasis mine].
Since a 'set' in this context comprises exactly one (or zero) of each building type, it does seem the original intent was to have only the unique buildings of one set provide road connection, not duplicates. So the programming laziness was at the outset, allowing all buildings of the set to daisy chain in any combination.
It really would be nice though if these new features could work as intended from the start. Most people don't read the descriptions in detail, and learn how these things work by trying them. And then we naturally assume that however they work is... how they're supposed to work. And plan accordingly. This makes an about face like this very frustrating, regardless of the original intent.
Perhaps when the developers make a relatively inconsequential slip like this in the players' favor, that has no significant effect on play balance, they could just say "Our bad"
- and let it stand?