5.7.* breaks website gettext translations

Where can we see the website in question?

I’ve reproduced the issue here at sample website https://cf7.qdv.cz. Hope example is clear – both areas (green and red) should be translated.

What other plugins and theme do you use on the site?

This sample site is using just CF7 5.7.4 and Polylang 3.3.1. No theme (just custom index.php with some Tailwind styling).

Try switching to the default theme and deactivating all plugins excluding Contact Form 7.

Why you are advised to deactivate plugins and switch to the default theme.

I don’t see a reason for this. As I wrote sample site is using just CF7 and Polylang which is needed for multilanguage. As for theme it cannot be simplier as it consists just from index.php. There are no functions at all (default WP theme is much more complex).

I can confirm similar issue, if I add a widget with CF7 form in sidebar all widgets added after that one will loose translation and get back to default english language. This happened recently