Different signature using WalletConnect

I use the same code for signing message:
```javascript
if (connector instanceof WalletConnectConnector) {
const messageLength = new Blob([signEvent]).size
const message = toUtf8Bytes(
"\x19Ethereum Signed Message:\n" + messageLength + signEvent
)
const hashedMessage = keccak256(message)

connector.walletConnectProvider.connector.signMessage([account.toLowerCase(), hashedMessage])
.then(response => {
console.log(response)
onSign({ response: response, error: null })
})
.catch(error => {
onSign({ response: null, error: error })
})
```

But the response when connecting through Alpha wallet is different than connecting through MetaMask wallet, both are connected through WalletConnect. I noticed there is a change regarding signing method several days ago(#2623) , could that be the reason that cause this difference?