Evault archive browser search from field

I'm in the pilot for EV 11 new installation and I found an issue with searching in EVault browser. When the archived message has SMTP address (someone@domain.com) in the from field and I'm trying to search the sender, if I type "someone" or the whole address as a keyword, search returns result for that message. But if I type something less than the whole string before @ sign (e.g. "someon" or "some", etc.), search doesn't return that message even though the criteria is set to "Contains any of".  Has any one seen it or has a solution for it?

Thank you.