ajax validation

[srakl]

When doing an ajax validation, i submit an empty form and the input shows an error. with class invalid like this

class=form-control form-control-lg is-invalid"

when i put a valid integter. it changes to

class=form-control form-control-lg is-valid"

then when i enter an invalid integer again, it doesn't change to is-invalid. It works fine before i used this plugin. Any idea why?

here is my javascript submit

<script>
            $(document).ready(function () {  
                var $form = $("#<?= $model->formName() ?>");
                $form.on("submit", function (event, messages) {
                    event.preventDefault();
                    $.ajax({
                        "type":"POST",
                        "url":$form.attr('action'),
                        "data":$form.serialize(),
                        "dataType":"json",
                        "cache": true, 
                        "success":function(data){
                            $("#tax").html(data.rtax);	
                        },     
                        "statusCode": {
                            429: function() {
                                alert("Exceeded request limit.");
                            }
                        }                          
                    });
                    return false;		
                });
            });
            </script>

my form

<?php 
                
                $form = ActiveForm::begin([
                    'id' => $model->formName(),
                    'enableAjaxValidation' => true,
                    'enableClientValidation'=> false,
                    'validateOnBlur' => false,
                    'validateOnChange' => false,
                    'options' => ['autocomplete' => 'off'],
                ]);
 ?>

<?= $form->field($model,'bla',
                ['template' => '
                {label}
                <div class="input-group mb-3">
                    {input}
                    <div class="input-group-append">
                        <span class="input-group-text">%</span>
                    </div>
                    {error}
                </div>
                {hint}
            '])->textInput(['class' => 'form-control form-control-lg']); ?>

<?php echo $form->field($model, 'reCaptcha')->widget(\kekaadrenalin\recaptcha3\ReCaptchaWidget::class) ?>

<?= Html::submitButton(Module::t('app', 'Calculate'), array('buttonType'=>'submit', 'class' => 'btn btn-lg btn-success btn-block shadow-sm')); ?>

<?php ActiveForm::end(); ?>