Why do I see agents logged in twice - under their own name and as Agent/name?

If you see agent logged in twice, once under their correct name and a second one under the name "Agent/agent name", often with a difference of a few seconds. Sometimes you will see that the correct name will log off at the end of the agent session, while the "Agent/agent name" will linger on for a while.

This is caused by not having "Friendly names" set - see Why do agents on a call show up with a different name? to fix this.