After this user is renamed himself with English, it still impossible to find and add him to the group.
Search on Russian
It seems search is not finds anything when used Russian language.
Hm... it may be because our search system works on phonetic tokens, and not fulltext (like traditional search engines). Perhaps Reds does not support non-English languages...!
This is a hopeless situation?
Not necessarily, @seti123 is doing some amazing work getting elasticsearch working with NodeBB. Perhaps it may work with Russian languages?