Return value of def request_raffle_winner() -> uint256 may be incorrect in the time window until fulfilled by VRF Coordinator:

We return the NFT ID of the winner-to-be. This means that the NFT ID will only be valid after VRF Coordinator calls rawFulfillRandomWords on the vyper contract and the ERC721._mint doesn't revert.

We cannot assume that requestRandomWords will always be followed by rawFulfillRandomWords from Chainlink Nodes because sometimes the subscription can also expire