yii\validators\StringValidator does not show custom message

In an app based on auto-generated Yii 2 Advanced Project Template I have modified 37th line of /frontend/models/SignupForm.php model (the line that uses yii\validators\StringValidator to validate length of the password). Changing it from:

['password', 'string', 'min' => Yii::$app->params['user.passwordMinLength']],


['password', 'string', 'min' => Yii::$app->params['user.passwordMinLength'], 'message' => 'Test'],

This seems to be ignored by the app and I am still getting default, framework-based message:

Password should contain at least 8 characters.

I have tried to change order of the parameters (which is totally pointless probably) into:

['password', 'string', 'message' => 'Test', 'min' => Yii::$app->params['user.passwordMinLength']],

Again, no effect.

In the very same place (rules() method of SignupForm model) I have many more validation rules (all of them comes from auto-generated app, no change on my side). I have modified messages displayed to the end user in all of them. All modifications are working and I see my custom message for every field and every validator (required, unique, email, etc.).

The only problem is with the string validator (yii\validators\StringValidator). It does display framework-default and not custom messages for both fields used in the signup form.

Here is the entire code of this method:

public function rules()
    return [
        ['username', 'trim'],
        ['username', 'required', 'message' => Yii::t('frontend-models', 'This field cannot be blank.')],
        ['username', 'unique', 'targetClass' => '\common\models\User', 'message' => Yii::t('frontend-models', 'This username has already been taken.')],
        ['username', 'string', 'min' => 2, 'max' => 255, 'message' => 'Test'],

        ['email', 'trim'],
        ['email', 'required', 'message' => Yii::t('frontend-models', 'This field cannot be blank.')],
        ['email', 'email', 'message' => Yii::t('frontend-models', 'This field field must contain a valid e-mail address.')],
        ['email', 'string', 'max' => 255],
        ['email', 'unique', 'targetClass' => '\common\models\User', 'message' => Yii::t('frontend-models', 'This email address has already been taken.')],

        ['password', 'required', 'message' => Yii::t('frontend-models', 'This field cannot be blank.')],
        ['password', 'string', 'min' => Yii::$app->params['user.passwordMinLength'], 'message' => 'Test'],

What am I missing?

As API (https://www.yiiframework.com/doc/api/2.0/yii-validators-stringvalidator#$message-detail) states:
[…] User-defined error message used when the value is not a string.

In your example ‘min’ rule is firing first and the custom message for it you can set by https://www.yiiframework.com/doc/api/2.0/yii-validators-stringvalidator#$tooShort-detail

Brilliant, thank you!