I'm not familiar with the mod, but I can suggest checking something...
In your queue_log data file/sql table, does the 'agent' field (4th field of each queue_log record) contain the same agent identifier throughout the events in a call (AGENTCALLBACKLOGIN/AGENTLOGIN, CONNECT, PAUSE, UNPAUSE, COMPLETECALLER, COMPLETEAGENT, etc.)?
The reason why I'm asking is because I believe the same value that was used for the AGENTCALLBACKLOGIN/AGENTLOGIN, must be the same when queue_log events such as CONNECT, etc. occur in order for QueueMetrics to be able to know which agent a particular call was answered by.
Hope it helps