I found the reason for this issue - @andreas66 u was right - the app itself require localization, but the way I did is not enough, instead, we also should add CFBundleLocalizations in info plist with required localizations as an Array of strings. Even if in official doc says that is's support only few localizations, we can add additional one there (using same locale code as lproj folders) and everything will works.
<key>CFBundleLocalizations</key>
<array>
<string>en</string>
<string>es</string>
<string>uk-UA</string>
</array>
An application can notify the system that it supports additional localizations through its information property list (Info.plist) file. To specify localizations not included in your bundle’s .lproj directories, add the CFBundleLocalizations key to this file. The value for the key is an array of strings, each of which contains an ISO language designator as described in “Language and Locale Designations.”
from old outdated doc...