When replying to a message with a friendly name, you notice your Notes client connecting to every server in your environment, alphabetically, upon hitting send. Depending on machine speed, internet connection, and the number of servers in the environment, this could take a long time (upwards of 1 minute) to complete.
Resolving the problem
This problem has been determined to be caused by a comma in the friendly name of the sender of the message to which you are replying to. Example:
"Name, User" <email@example.com>
Hitting send on a reply to a message with this kind of friendly name will cause the issue described above. Manually removing the comma fixes the issue.
This has been reported to Quality Engineering under SPR # JRGE8FMM9R; and it is currently under investigation.