function _deriveHookHash(Hook memory hook) internal view returns (bytes32) {
  // Derive and return the hook as specified by EIP-712.
    return
        keccak256(
-           abi.encode(_HOOK_TYPEHASH, hook.target, hook.itemIndex, hook.extraData)
+           abi.encode(_HOOK_TYPEHASH, hook.target, hook.itemIndex, keccak256(hook.extraData))
        );
}
// Construct the Item type string.
bytes memory itemTypeString = abi.encodePacked(
    "Item(uint8 itemType,uint8 settleTo,address token,uint256 amount,uint256 identifier)"
);

// Construct the Hook type string.
bytes memory hookTypeString = abi.encodePacked(
    "Hook(address target,uint256 itemIndex,bytes extraData)"
);

// Construct the RentalOrder type string.
bytes memory rentalOrderTypeString = abi.encodePacked(
    "RentalOrder(bytes32 seaportOrderHash,Item[] items,Hook[] hooks,uint8 orderType,address lender,address renter,address rentalWallet,uint256 startTimestamp,uint256 endTimestamp)"
);

...

rentalOrderTypeHash = keccak256(
    abi.encode(rentalOrderTypeString, hookTypeString, itemTypeString)
);
function test_EIP712_encoding() public {
		// Copied from the reNFT codebase
    bytes memory itemTypeString = abi.encodePacked(
        "Item(uint8 itemType,uint8 settleTo,address token,uint256 amount,uint256 identifier)"
    );
    bytes memory hookTypeString = abi.encodePacked(
        "Hook(address target,uint256 itemIndex,bytes extraData)"
    );
    bytes memory rentalOrderTypeString = abi.encodePacked(
        "RentalOrder(bytes32 seaportOrderHash,Item[] items,Hook[] hooks,uint8 orderType,address lender,address renter,address rentalWallet,uint256 startTimestamp,uint256 endTimestamp)"
    );
		// protocol implementation
    bytes32 rentalOrderTypeHash = keccak256(
        abi.encode(rentalOrderTypeString, hookTypeString, itemTypeString) // <-----
    );

    // correct implementation
    bytes32 rentalOrderTypeHashCorrect = keccak256(
        abi.encodePacked(rentalOrderTypeString, hookTypeString, itemTypeString) // <-----
    );

    // the correct typehash
    bytes32 correctTypeHash = keccak256(
        "RentalOrder(bytes32 seaportOrderHash,Item[] items,Hook[] hooks,uint8 orderType,address lender,address renter,address rentalWallet,uint256 startTimestamp,uint256 endTimestamp)Hook(address target,uint256 itemIndex,bytes extraData)Item(uint8 itemType,uint8 settleTo,address token,uint256 amount,uint256 identifier)"
    );

    assertNotEq(rentalOrderTypeHash, rentalOrderTypeHashCorrect);
    assertNotEq(rentalOrderTypeHash, correctTypeHash);
    assertEq(rentalOrderTypeHashCorrect, correctTypeHash);
}
rentalOrderTypeHash = keccak256(
-    abi.encode(rentalOrderTypeString, hookTypeString, itemTypeString)
+    abi.encodePacked(rentalOrderTypeString, hookTypeString, itemTypeString)
);
function _deriveOrderMetadataHash(
    OrderMetadata memory metadata
) internal view returns (bytes32) {
    bytes32[] memory hookHashes = new bytes32[](metadata.hooks.length);

    for (uint256 i = 0; i < metadata.hooks.length; ++i) {
        hookHashes[i] = _deriveHookHash(metadata.hooks[i]);
    }

    return
        keccak256(
            abi.encode(
                _ORDER_METADATA_TYPEHASH,// OrderMetadata(uint8 orderType,uint256 rentDuration,Hook[] hooks,bytes emittedExtraData)
								// <---- misses uint8 orderType
                metadata.rentDuration,
                keccak256(abi.encodePacked(hookHashes))
								// <---- misses bytes emittedExtraData
            )
        );
}
