Duplicate invoice error in autoinvoice

 Hi,

I am stuck only in one scenario and invoice is not creating and th problem is occuring only in PRODUCTION while the scenario is running on TEST instance is ok.

We are using transaction source type is IMPORTED and automatic transaction number and batch is not checked.

The scenario is:
2 sales order=1 delivery=1 invoice

Also we are using   interface_line_attribute3  (Delivery) optional grouping rule. 

When the lines coming in interface,i enter the invoice number same in the same delivery number.When i run the autoinvoice program,the error is "duplicate invoice is not generated"

While the same scenario is tested in TEST instance and creating one invoice.