Solution for this topic

But as for “Search results for” there are 2 strings for search results page.

One resides in titlebar.php (the one that I can translate),

the other “Search results for:” which is shown on breadcrumbs on the search result page (the one that I can’t translate).

I could confirm the issue on my test site therefore notified the theme developer about this so that it will be fixed.

The issue will be fixed ASAP.

In the meanwhile you can resolve the issue by using the attached modified child theme of Jevelin theme.