Workflow 2013 Execute SQL fails after 5 minutes. Timeout setting in the connection string is not taking effect

Hello,

I have long running query and it is failed with "Error performing database operation. Timeout expired.  The timeout period elapsed prior to completion of the operation or the server is not responding."

My version is Nintex Workflow 2013 (3.1.6.0).

It fails even if I use following connection string with 1 hour timeout "Data Source=SQL; Integrated Security=SSPI; Connection Timeout=3600"

Is this by design? We should have the power to control the timeout.

Thanks,

Ivan