Problem with localization in some parts

Hello! First of all I would like to **thank you for that much useful package**, it helps a lot.
I've almost managed all issues myself, but can't find origin of problem with localization.
I am using wordpress site and want to insert gutenberg at some my page in admin menu.
I've done all by readme instructions and over some time got working instance, but what is the problem -
that some parts of editor are still in english in the same time when at the standard post editor they all are in russian,
It is so despite I use @wordpress/scripts and point all js-dependencies in php and of course use iso php class to load all necessary stuff, connect editor settings from iso class to IsolatedBlockEditor.settings.editor over json and so on. Can you please help me, just to point some tip, what can I check else?
For example here are images with editor in my page and in standart editor:

Start with the README's localization setup and the PHP dependency-loading path, then inspect how IsolatedBlockEditor.settings.editor is populated from JSON and compare it with the standard WordPress post editor. Reproduce the Russian locale and identify which editor strings remain English; done means the embedded editor's relevant UI is localized consistently.

Written by the indexing model from the issue text.