As per the ERC721 standard, the transfer function shouldn't emit an Approve event, as clearing the approval is implicit in the Transfer event.

Docs regarding Approve event:
```
    /// @dev This emits when the approved address for an NFT is changed or
    ///  reaffirmed. The zero address indicates there is no approved address.
    ///  When a Transfer event emits, this also indicates that the approved
    ///  address for that NFT (if any) is reset to none.
```
[EIP-721](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md)