Event ID 1057 Agent "" went async

We have been seeing the following event logged on our MS Exchange 2013 server:

Log: Application
Type: Error
Event: 1057
Agent Time: 2014-09-12 15:57:55Z
Event Time: 07:57:24 PM 12-Sep-2014 UTC
Source: MSExchange Extensibility
Category: MExRuntime
Username: N/A
Computer: server.domain.name
Description: Agent 'Ninja Routing Agent' went async but did not call Resume on the new thread, while handling event 'OnRoutedMessage'

I know the Ninja Routing Agent is used by the VIPRE anti-spam program that is also installed on the server. I have tried researching this error on general Exchange agents but have not found much. Is this something that needs to be reviewed by the application vendor?