The hashCode() implementation of FileParameterValue.java only considers the location. Often times the file parameter is passed with the same file name and thus the same location, but the contents are different. The hashCode() should consider the contents so that the queue will queue the WaitingItem for each invocation that has different file parameter contents.
The current workaround is to add a string parameter that provides a unique string like a timestamp and ldap name. This is not ideal having to do an extra parameter to differentiate the parameter action list.