Dovecot 2.2.31 Incorrect Search

Hi. I have installed dovecot 2.2.31 and fts plugin with Apache Solr 6.6.1. I have found that imap search is not correct in my dovecot. For example, I want to find email from user s.chistiakov@example.com. I run IMAP command "SEARCH FROM s.chi" and result is null. But if I run IMAP command "SEARCH FROM s.chistiakov" I get list of emails from this user. Why does this happen and how to fix it? Help me please ) Thanks.

Result of my actions in telnet: https://hastebin.com/fewanacafu.md Dovecot config: https://hastebin.com/noqehimaxu.makefile