addmultisigaddress creates an address respecting the setting, being unable to generate a specific type of address without also adding it to the wallet seems wrong.

I suppose in the future `addresstype` may be refactored to be wallet-specific, which would leave this non-wallet rpc call without an argument. Perhaps there should just be an optional parameter to set it.
constexpr int64_t MAX_SLEEP_TIME = 100000000; 
    if (nSleepTime > MAX_SLEEP_TIME) {
        nSleepTime = MAX_SLEEP_TIME;
    }
    if (strWalletPass.length() > 0)
    {
        if (!pwallet->Unlock(strWalletPass)) {
            throw JSONRPCError(RPC_WALLET_PASSPHRASE_INCORRECT, "Error: The wallet passphrase entered was incorrect.");
        }
    }
    else
        throw std::runtime_error(
            "walletpassphrase <passphrase> <timeout>\n"
            "Stores the wallet decryption key in memory for <timeout> seconds.");
    pwallet->TopUpKeyPool();
    pwallet->nRelockTime = GetTime() + nSleepTime;
    RPCRunLater(strprintf("lockwallet(%s)", pwallet->GetName()), std::bind(LockWallet, pwallet), nSleepTime);
    return NullUniValue;
}
static UniValue walletpassphrasechange(const JSONRPCRequest& request)
{
    std::shared_ptr<CWallet> const wallet = GetWalletForJSONRPCRequest(request);
    CWallet* const pwallet = wallet.get();
    if (!EnsureWalletIsAvailable(pwallet, request.fHelp)) {
        return NullUniValue;
    }
    if (request.fHelp || request.params.size() != 2) {
        throw std::runtime_error(
            "walletpassphrasechange \"oldpassphrase\" \"newpassphrase\"\n"
            "\nChanges the wallet passphrase from 'oldpassphrase' to 'newpassphrase'.\n"