This page describes what happens if multiple directory servers are defined in Confluence. For example you might have an internal directory server and you might also have a connection to an LDAP external server or use multiple types of other user directories. When you define multiple directory servers in your system, you need to specify the directory order of the different directory servers in your system .
Avoid multiple usernames across directories:
If you connect to more than one directory server, we recommend that you make sure your username is unique across the directory server. For example: We do not recommend that you define
jsmith
a . The reason for this requirement is to avoid confusion in the system, especially if you switch directory servers. Modifying the order in which the directory servers are sorted also modifies the order in which usernames are referenced.
https://www.cwiki.us/display/CONFLUENCEWIKI/Managing+Multiple+Directories