Got another reply for them. So both cashbacks are applicable
****
We had checked the issue and could confirm that you are eligible for both the offers listed.
They are two separate orders and two different offers and so you are eligible towards for both of them.
For SBI Cash back, the amount will be credited to the card holder's account by Bank latest by 28 August 2018.
For Gift Card offer, Amazon Pay Balance Cashback will be credited to the customers Amazon.in account latest by May 25, 2018.
***