When I translate a page from a popup, the language I set is not applied.

HU_JA_JA

Check that the target language setting is not English.

Translate the page into any language (English).

Then, English is set instead of the selected language.

I am accustomed to translating pages from the pinned extension icon, so I expect it to translate immediately to the specified language even when translating from the popup window.
For your reference, when I initiate page translation from the right-click menu, it translates to the correctly set language.

Giorgio

Thanks for the report! Will be fixed in the next extension release.