Gas line “appliance connectors”

The yellow flexible pipe pipe on the gas line to the furnace is a problem. Flexible connectors are not permitted to go through any wall of any kind. The metal wall of the furnace cabinet becomes the excluding factor. Equally bad is that the edges of the hole in the cabinet are sharp and could cut through the lightweight flex pipe if the furnace blower developed a vibration which would result in a gas leak. There always should be black iron pipe connected to the furnace control module, that extends out of the cabinet and then connects to the flex connector. Even better is that a flex connector is not used (they are a lazy installer demonstrating his lack of skill) and the complete installation is black iron pipe (or CSST flexible gas line, not to be confused with the cheaper and lesser flex connector)