"Mobile Header On" loads a simplistic (like non-CSS) version on mobile

Hello,

Thanks for the great theme! Its speed makes me feel like I'm working on my local computer.

Theme: 2.4.2
Premium: 1.9.1

This is not urgent, I "solved" the issue by switching Customize > Layout > Header > Mobile Header to off. This version looks good as well even though I would prefer the Mobile Header On one. But I wanted to let you know.

When that option is enabled a simplistic version (One looks like it is written by primitive HTML) of the page shows up on mobile. On homepage everything looks good, in sub-pages (pages and posts) primitive version comes up.

Interestingly enough, website loads well on mobile simulation of Chrome developer tools on desktop, but not on my Samsung Galaxy phone's Chrome or Samsung Internet browsers. Thus issue seems to be browser-dependent.

The screenshot I attach below is from a large website with lots of plugins, however I had the same issue in a new website that almost had no plugins as well. Difference is issue went away when I refreshed the website with few plugins, but it does not go away if I refresh my main site. I was not able to reproduce the issue in the new website therefore I am not sure what exactly is causing this behavior.

If this issue is familiar and there is a fix you can suggest then great. If not, I can live with "mobile header off" as well.

Thanks