OptimisticEthereum UUPS proxy verification

Hello, I'm creating an UUPS contract on the Optimistic network using hardhat and the contract of proxy is not verified.
I can verify implementation but not the proxy contract itself.
Etherscan says:
" The proxy contract at 0x3E818Baf68F6465b2d97604f072CE6E402B906F7 does not seem to be verified."
The same is for the kovan-optimistic (testnet)

:1234: Code to reproduce

// Contract code
import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/proxy/utils/UUPSUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";

contract StrategyStorage is Initializable, UUPSUpgradeable, OwnableUpgradeable {

const StrategyStorage = await hre.ethers.getContractFactory("StrategyStorage");
const strategy = await upgrades.deployProxy(StrategyStorage, [args],
        initializer: "initialize",
        kind: "uups"
await strategy.deployed();

:computer: Environment

"@nomiclabs/hardhat-ethers": "^2.0.3",
"@nomiclabs/hardhat-etherscan": "^2.1.8",
"@nomiclabs/hardhat-truffle5": "^2.0.2",
"@nomiclabs/hardhat-waffle": "^2.0.1",
"@nomiclabs/hardhat-web3": "^2.0.0",
"@openzeppelin/contracts": "^4.3.3",
"@openzeppelin/contracts-upgradeable": "^4.4.0",

BSC testnet is verifying proxy with the same code

If you use the latest version of the hardhat-upgrades plugin, you can try using the new verify task (which extends hardhat-etherscan's verify) to verify your proxy. See https://docs.openzeppelin.com/upgrades-plugins/1.x/api-hardhat-upgrades#verify

Hello, ericglau.

This task automatically founds the implementation and then says:
"Implementation 0xf6cF656b31b27Eef735714aDe2fD39DF5edbc9FF already verified."

And it really is. Implementation is verified but proxy is not.

It should have proceeded to verify the proxy after that message.

Can you enable debug with

export DEBUG=@openzeppelin:upgrades:*

and run the verify task again, then provide the console output here?

I found the root cause, i was using library @nomiclabs/hardhat-etherscan": "3.0.4" which seems to be bugged for now.

Once downgraded to 3.0.3 everything works. Thanks for quick responses!