Can not create muxed account. TypeError: med25519 not set

[nqs1901]

Describe the bug

What version are you on?
"@stellar/stellar-sdk": "^13.1.0"

To Reproduce
const StellarSdk = require('@stellar/stellar-sdk');
const id = '34546';
const muxed = StellarSdk.MuxedAccount.fromAddress(address, id );

TypeError: med25519 not set

Expected behavior
A clear and concise description of what you expected to happen.

Additional context
Add any other context about the problem here.

[Shaptic]

What is address? It should be an instance of an Account. It appears to be an instance of string, instead.