[Ethereum] Invalid number of arguments error for getter function with no passed arguments

I am receiving this error when trying to call the getUsers getter function from the contract below: Invalid number of arguments to Solidity function. Running on Truffle in develop mode.

mapping (address => User) Users;
address[] usersByAddress;

struct User {
    string handle;
    bytes32 city;
    bytes32 state;
    bytes32 country;
}

function registerNewUser(string handle, bytes32 city, bytes32 state, bytes32 country) returns (bool success) {
    address thisNewAddress = msg.sender;
    if(bytes(Users[msg.sender].handle).length == 0 && bytes(handle).length != 0){
        Users[thisNewAddress].handle = handle;
        Users[thisNewAddress].city = city;
        Users[thisNewAddress].state = state;
        Users[thisNewAddress].country = country;
        usersByAddress.push(thisNewAddress);  
        return true;
    } else {
        return false;       
    }
  }

//getters
function getUsers() view returns (address[]) { return usersByAddress; }

function getUser(address userAddress) view returns (string, bytes32, bytes32, bytes32) {
    return (Users[userAddress].handle, Users[userAddress].city, Users[userAddress].state, Users[userAddress].country);
}

Let's say you deploy this contract in Truffle develop testnet and get an instance of the object x. I can create a user by sending the transaction x.registerNewUser("Bob123","Orlando","FL","USA"). Then I run x.getUser(web3.eth.accounts[0]) and get the following array:

[ 'Bob123',
'0x4f726c616e646f00000000000000000000000000000000000000000000000000',
'0x464c000000000000000000000000000000000000000000000000000000000000',
'0x5553410000000000000000000000000000000000000000000000000000000000' ]

This is expected since the last 3 elements in the array are type bytes32. I expect x.getUsers or x.getUsers.call() to return an array of one address (my address at web3.eth.accounts[0]) but instead get the invalid Solidity arguments error even though there are no arguments passed into getUsers.