Hi Ashish,
You cannot export only a single stack from a dual stack system, as it is not supported. Check the guide below:
https://service.sap.com/~sapidb/011000358700001419502012E
1.5 Constraints
When your system is a dual-stack system and you perform a system copy, your source system is copied to the target system as a whole. This means, it is neither possible to exclude a single stack from the system copy nor to copy a separate stack only.
When your system is a dual-stack system and you perform a system copy, your source system is copied to the target system as a whole. This means, it is neither possible to exclude a single stack from the system copy nor to copy a separate stack only.
You should start the system copy from scratch and follow the procedure described on the guide
Regards,
Alessandro Parolin