Hi Sambarn,
What is the occurance of Order Number at target side,as per mapping logic what you have written for the data what you have tested you will have two values for order number 0000,1223-ER.
First occurance order number value will have 0000,second occurance order number will have 1223-ER.
if you have set ordernumber occurance to 1 then you will see output value 0000.
what is your requirement?
Regards,
Raj