0x prefix

> Asynchronous method used to determine if the transaction signer manages the address passed in. We recommend the transaction signer account for addresses that start with "0x" as well as those that do not.

I recommend you pick a format and stick to it

https://github.com/ethereum/ethereumjs-util/blob/master/index.js#L232-L238

Start with index.js at the linked ethereumjs-util address-handling code and inspect how addresses with and without the 0x prefix are compared. Check the repository's existing tests, if any, for transaction signer address handling; done means the provider consistently accepts or normalizes both address formats without changing signer detection.

Written by the indexing model from the issue text.