If you compose a message that includes a Simple Mail Transfer Protocol (SMTP) one-off address and display name on the Cc line, and then send the message to a Lotus Notes recipient, the Notes recipient may reply all to the message. When you view the reply in an e-mail client, the SMTP address may appear in the following format:
"User1@Host1@SMTP@Domain1" <User1@Host1>@SMTP@Domain1
Note that multiple SMTP addresses are appended, which is not the correct format. As a result, if you attempt to reply all to the original reply, the new reply cannot be delivered to the SMTP recipient. This issue is known to occur when the messages are sent between an Exchange Server computer and a Notes Release 5 (R5) server through the Exchange Notes Connector, and the Notes recipient uses a Notes R5 client to reply all to the original message.
In addition, if you compose a new message that includes an implicitly encapsulated SMTP address and display name on the Cc line, and then send the message from a Notes R5 client to an Exchange Server recipient, the address may not be formatted correctly when the Exchange Server recipient views the message in an e-mail client. However, if the Exchange Server recipient replies all to the message, the reply is successfully delivered to the SMTP recipient.