Sometimes agents are resolved incorrectly

[Kim, Go Joong]

Dear workflowers,
 
I designed a workflow and tested it one time and another successfully.
But sometimes agent resolution is failed.
The possible agents of a step is all users because it is set as general
task and responsible agent is set as workflow initiator.
So the recepient must be workflow initiator.
But sometimes the agents are resolved as WF-BATCH, and the status of step
is pending as 'Ready'. So I can't continue the workflow.
 
Is there any body knowing why this symtom occurred?
 
Regards,
Gojoong Kim (Steve)