Key cannot be null

Hi.

We are calling a timer every 5 minutes to check for new data on a remote database.  Ever since we updated our platform from OS10 to OS11 we get the following error when there is no new data on the remote database:

Key cannot be null.
Parameter name: key

This error doesn't cause any problems for the users but it fills up our error log pretty quickly.  

My question is this:
What causes this error in OS11 when this was running smoothly for a few years in OS10?
This is the call that we have been using:

/* %LogicalDatabase%=GetLogicalDatabase({MyDatabase}) */
EXEC [dbo].[GW_PEEK_ASYNC]
    @Username, 
    @Password,
    @ServiceId    
    commit