Ethereum core developer Tim Beiko has reported a bug seen on Metamask during the Sepolia fork: that of the ETH balance not updating after Beacon Chain withdrawals.
Beiko describes the bug in a Github report: When a withdrawal happens on the beacon chain, it increments the accounts' balance without a transaction, similar to how PoW rewards were handled. On MetaMask, these balance updates are not reflected.
Shapella PSA for wallet devs: beacon chain withdrawals *don't* create a transaction on the EL. This means that if you're scanning incoming txns to an address to update its balance, you won't process withdrawal balance updates 👀— timbeiko.eth (@TimBeiko) February 28, 2023
A screenshot from Sepolia was shared, where the Metamask balance was much lower than the balance shown on Etherscan.
According to the Github page, users that run validators on post-Shanghai networks (now Sepolia or Zhejiang) and then wait until a partial or full withdrawal occurs may get an error message as a result of the bug. On Metamask, the balance will not show the amount withdrawn.
On Feb. 28, the Sepolia testnet successfully underwent the "Shapella" upgrade, which mixes the names of the upcoming Shanghai and Capella hard forks.
Sepolia hard fork
The much-awaited Shanghai upgrade, which will allow validators to withdraw staked ETH, is getting closer to reality thanks to Ethereum testnet Sepolia's successful replication of withdrawals in the Shapella upgrade.
The Shapella hard fork occurred on Sepolia at epoch 56832 at 11:04 p.m. ET on Feb. 28 and was completed at 11:17 p.m. ET.
The second of three testnets to go through this simulation is Sepolia. This testnet upgrade, however, was on a closed testnet, meaning that only the Ethereum core developers run validators on this testnet, unlike the Zhejiang testnet.
The upgrade will be made available on the Ethereum Goerli testnet as the final stage before the Shanghai fork goes live on mainnet.