[otrs] Duplicate replies send to customers

When sending mail replies from the agent web interface, it happens that customers receive duplicate mails. In practice, when an agent sends a reply from the web interface, in the To field the following address is displayed: "mail\*customer\.com" then the reply is sent twice (* stands for @) If I correct the the entry in the To field in: mail*customer.com then teh reply is correctly sent once. Any idea about the reason for such a weird behaviour? -- Gabriele D'Andrea