Ionic 4 navitagion forward not working with named outlet

I am trying to implement some kind of navigation history using android back button, but I can’t get it to work with named outlets.

I do

this.navCtrl.navigateForward([{outlets: { masterNav: url}}]);

And the page displays well, but when I do

this.navCtrl.pop() 

It doesn’t get to previous page like if it was root.

What am I missing ?