Hello,
I am having the exact same problem, and this was certainly working properly a few weeks ago.
When visit the site, the Blog page is shown, although a Static pages is configured in the Reading settings. If I type thedomain.com/about, I can see the correct page, but I can not configure the theme to show this.
I have disabled all plugins, and swapped to 20-10 to test. It did not work with the base settings.
I have noticed that when I selected the HOME page and then reviewed the page permalink settings, it was changed from domain.com/about to be just domain.com. This would make sense, as it is the landing page, but I thought it was something mis-configured with mod_rewrite. I checked and am pretty sure it has not changed, and as I mentioned, it was working in the past.
Any update on this problem? there has been no feedback for a month.