Just wanted to report something I encountered recently in the Customizer. It seems to be a refresh issue.
If you have your site’s Layout > Header > Header Width set to “Full” and your Inner Header Width set to “Contained” like I do, and then you change the Header Width to “Contained” and then back to “Full” you will notice that the Inner Header Width (which was set to “Contained”) will ignore its previous setting and expand the full width of the area, which can be a little misleading. Surprisingly, refreshing the Customizer shows the Inner Header Width is still preserved as contained, even though the live preview showed everything fullwidth. This is small but just wanted to bring it to your attention.