I have set-up an fresh T4 builder site, created three pages for this demo. All the header blocks that use joomlas navigation module are missing the burger icon.
Also, the 'out of the box' styling on some of them is wrong and you can't see the page names due to the font colour being them same colour as the background. This will confuse the hell out of your new customers and our clients!
See video below.
https://streamable.com/cgoy05