Two types of Gst refunds for the same period

The taxpayer had claimed refund for the month of Oct 18 under "Refund due to accumulated itc arising out of export without payment of duty". And the same was sanctioned. Now he has again filed a claim under "Refund due to inverted duty structure" for the above mentioned period producing the same invoices on which claim has already been sanctioned. So whether the taxpayer is eligible for the refund again on the same invoices. The only difference is that the type of refund has changed but documents are the same