It's common to see international companies and organizations having a global web site with several country web sites. The country web sites is often translated to the countries' own language, which enables native language only readers to consume the content of the web site. This is very good and widens the audience of the web site.
When moving from "left to right"-languages (LTR) to "right to left"-languages (RTL) the top navigation menu language change accordingly. However the navigation order does not change. It is still in the same reading order as the site was first developed. This means that the nominal order of top navigation is reversed on RTL sites where the most important top menu item is placed last.
To solve this one can always develop a mirror site (!) for RTL sites where the most important top navigation item is placed to the right. But from the frameworks I know and work with, this comes with a substantial cost. However, from a usability perspective this should be done.
Should we mirror top navigation order between left to right-languages and right to left-languages?