ecrecover does not return consistently depending on digest despite correct signer

[snario]

Using the following code:

contract ECRecover {
	function recover (bytes32 nonce, uint8 v, bytes32 r, bytes32 s) constant returns (address) {
		return ecrecover(nonce, v, r, s);
	}
}

For some inputs, e.g., with the nonce variable here that an account signs, ecrecover does not correctly recover the address.

Expected Behavior

ecrecover should return the address of the account that signed the message.

Current Behavior

ecrecover does not return the address of the account that signed the message for "some" digests. I haven't figured out the pattern yet.

Steps to Reproduce (for bugs)

I've made a repo here: https://github.com/snario/reproducible-ganache-bug

Context

I'm trying to sign messages roughly following the direction of EIP 155. GnosisSafe already implements this.

Your Environment

See the repo, ran inside a fresh ubuntu Docker container.

[snario]

Seems like an ethers.js bug.

ethers-io/ethers.js#208