It’s more about residues that get left behind and trapped in the rubber gasket. Keeping a dour open, although helpful, simply isn’t enough. A big part of the problem is due to the limited water use. Things don’t fully rinse.

I don’t know, it’s a major problem that people report and I’ve experienced myself. There’s even a fan you can buy and put into the machine. But hey if you haven’t experienced problems then that’s great.