Did they fix air recirculate problem in 2019 GM

[1 more Brian]

 2018 GMC Sierra let's all of the fumes in took it to 2 dealership  the first dealer said That's supposed to happen second dealer said definitely a problem. now it's full of mildew any recommendations other than buying a Ford to fix this 

[cltsig]

Had a 2016 Yukon and let in fumes when on recirc. One of the reasons we sold it (booming was #1 reason). I heard that was by design - read it on here.  I have a 2019 LTZ and I've been behind the smokiest, smelliest diesel trucks and not a whiff. GM seems to have gotten it right. 

[1 more Brian]

That gives me hope and maybe they'll fix mine