Some translation strings are not available in version 10

Problem/Motivation

It seems that certain translation strings are not present in the files of versions 10 and higher

Steps to reproduce

Install opensocial in a language other than English, activate and update the interface translations.
For example, “What are you looking for?” in the search window, is not translated.
Import the latest translation file 12.0.2 or one of the files higher than version 10.
"What are you looking for ?" in the search window, is still not translated
Import the latest 8.x-9.18 translation file.
In my case, 258 strings are imported.
"What are you looking for ?" in the search window, is translated

Proposed resolution

I don't understand how it works, but make sure that all the translation strings used are imported into the latest version
Thank you so much

Remaining tasks

User interface changes

API changes

Data model changes