I had a 2003 Sierra and 2012 Silverado both caught the leprosy bug around the rear wheel wells. My friend's 2018 Silverado is also getting it. I'll never buy another GM truck as long as I live in a northern climate.
Chris
Our salt roads in winter and the salt ocean air sure beat up the bodies in our auto's .
But like you said some are worse than others.
My ProMaster 2014. nothing showing where I look so far. But it iss just a tool box on wheels for me.
David