https://github.com/bitcoin/bitcoin/blob/5180a86c96bc05d2a731f70f36aae28ab5a3fad4/src/qt/sendcoinsdialog.cpp#L339

I think this is %1, not %2
if(!ctx.isValid())
    {
        
        fNewRecipientAllowed = true;
        return;
    }
    
    WalletModelTransaction currentTransaction(recipients);
    WalletModel::SendCoinsReturn prepareStatus;
    
    CCoinControl ctrl;
    if (model->getOptionsModel()->getCoinControlFeatures())
        ctrl = *CoinControlDialog::coinControl;
    updateCoinControlState(ctrl);
    prepareStatus = model->prepareTransaction(currentTransaction, ctrl);
    
    processSendCoinsReturn(prepareStatus,
        BitcoinUnits::formatWithUnit(model->getOptionsModel()->getDisplayUnit(), currentTransaction.getTransactionFee()));
    if(prepareStatus.status != WalletModel::OK) {
        fNewRecipientAllowed = true;
        return;
    }
    CAmount txFee = currentTransaction.getTransactionFee();
    
    QStringList formatted;
    for (const SendCoinsRecipient &rcp : currentTransaction.getRecipients())
    {
        
        QString amount = "<b>" + BitcoinUnits::formatHtmlWithUnit(model->getOptionsModel()->getDisplayUnit(), rcp.amount);
        amount.append("</b>");