Gas Flows through unbuilt pipe

this is a parallel pipe/wire build bug - since they're both side by side, you tell them to build the link between two existing pipes, there's nothing to build, the connection just happens to be between two tiles right next to each other. so the blueprint is a formality.

The same thing can be done with parallel wires. Simply telling the sim you want them connected connects them without dupe intervention since the tiles are right next to each other. Usually I don't see the blueprint when this happens, so that's kind of new to me.