Been following this from when it emerged on the heating failure post. When is the bag supposed to have been deleted? My March 2019 car has one. Mine looks quite robust - not like the tea bag thing in the YouTube video! I’m not concerned at this stage in my car’s life, but interested.
I would agree with the view that coolant is designed to inhibit corrosion, so why the need for this bag? I’m guessing that it’s a bit like a magnetic drain plug - leaching corrosive particles from the coolant.