Changes have been made in R5.0.4 to the way the Internet Mail Address field is administered in Location documents.
Previously, on computers where users with separate IDs and Location documents shared a single physical machine and Notes client installation, switching user IDs could cause mail for a specified Internet user to be return-addressed for a different Notes Mail user on the same computer. When Person A sent Internet mail from their proper 'Person A' location, Person B on the same machine would receive all the replies to that e-mail.
The Notes Dynamic Configurator's automatic update of these user-specific fields has been altered in R5.0.4. When switching user IDs, The Notes Dynamic Configurator would sometimes change the "Internet mail address" stored in the Location document. With this code change, the Configurator overwrites the address only if the address was previously set by the current user.