I’m not using any search plugin.
And unfortunately, due to hypersecurity, I cannot give you any access.
As no changes were brought to the theme, I guess that if you test on your demo, you’re likely to notice that it doesn’t work either (on post content/body yes, but not on the titles)?
I have tested it on my test site and it’s working fine for me using below latest version of Jevelin theme as displayed in the attached screenshot.
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This can be due to plugin conflict on your site so please try temporary deactivating all plugins except Unyson plugin and WpBakery page builder plugins and see whether everything works fine and then enable the plugins one by one to see which plugin is conflicting if any.