Product attribute in filter

My issue is quite simple to resume :

I have 2 products attribute. One of them is already appearing in my filter front panel. The other is not.

I have almost the same configuration for both of them.
What’s tilting me is that I think the configuration is kind of ignored (indeed with that configuration I don’t think neither of these attributes should be added to the filter panel) but one is.

As you can see here is what I have under Product Attributes

The first one is already appearing in filter, but not the second one.

Inside their configuration everything is the same

So my issue is : Why the second one isn’t appearing (I have enought data to make it appear, so it’s not because I don’t have any products with that attributes).
Is there some place in the code where I can check what is going on ?

First attributes properties (the second one is the exact same except he has system values).

Attributes creation :

$eavSetup = $this->eavSetupFactory->create(['setup' => $setup]);  

$eavSetup->addAttribute(
        MagentoCatalogModelProduct::ENTITY, 'longueur_tasse_vertuo', [
            'type'  => 'text',
            'backend' => 'MagentoEavModelEntityAttributeBackendArrayBackend',
            'frontend' => '',
            'label' => 'Longueur de tasse Vertuo',
            'input' => 'multiselect',
            'class' => '',
            'source' => 'CpyCatalogModelConfigProductCupSizeVertuooption',
            'global' => MagentoEavModelEntityAttributeScopedAttributeInterface::SCOPE_STORE,
            'visible' => true,
            'required' => false,
            'group' => '',
            'sort_order' => 203,
            'searchable' => false,
            'filterable' => true,
            'comparable' => false,
            'used_in_product_listing' => true,
            'visible_on_front' => true
        ]
    );

The sources file defines (which are the default system values.

public function getAllOptions()
{
    $this->_options = [];
    $this->_options[] = ['label' => 'Espresso', 'value' => '1'];
    $this->_options[] = ['label' => 'Double Espresso', 'value' => '2'];
    $this->_options[] = ['label' => 'Gran Lungo', 'value' => '3'];
    $this->_options[] = ['label' => 'Mug', 'value' => '4'];
    $this->_options[] = ['label' => 'Alto', 'value' => '5'];

    return $this->_options;
}

I can’t find any setup for the first one that is already appearing.

Also if It can help I have this in a ‘product_cofee.xml’ layout

<block class="MagentoCatalogBlockProductViewDescription" name="product.info.cafe.cupsize" template="Magento_Catalog::product/view/cafe/cup-size.phtml" before="product.info.price" >
    <arguments>
        <argument name="at_call" xsi:type="string">getLongueurTasse</argument>
        <argument name="at_code" xsi:type="string">longueur_tasse</argument>
        <argument name="at_type" xsi:type="string">text</argument>
        <argument name="css_class" xsi:type="string">product-nespresso-cupsize</argument>
        <argument name="at_label" xsi:type="string">Taille des tasses :</argument>
        <argument name="add_attribute" xsi:type="string">itemprop="nespresso-cupsize"</argument>
    </arguments>
</block>

<block class="MagentoCatalogBlockProductViewDescription" name="product.info.cafe.cupsize.vertuo" template="Magento_Catalog::product/view/cafe/vertuo/cup-size.phtml" before="product.info.price" >
    <arguments>
        <argument name="at_call" xsi:type="string">getLongueurTasseVertuo</argument>
        <argument name="at_code" xsi:type="string">longueur_tasse_vertuo</argument>
        <argument name="css_class" xsi:type="string">product-nespresso-cupsize-vertuo</argument>
        <argument name="at_label" xsi:type="string">Taille des tasses :</argument>
        <argument name="add_attribute" xsi:type="string">itemprop="nespresso-cupsize"</argument>
    </arguments>
</block>

#EDIT

My query

2020-07-24T08:37:17+00:00 INFO (6): SELECT `main_table`.`entity_type_id`, `main_table`.`attribute_code`, `main_table`.`attribute_model`, `main_table`.`backend_model`, `main_table`.`backend_type`, `main_table`.`backend_table`, `main_table`.`frontend_model`, `main_table`.`frontend_input`, `main_table`.`frontend_label`, `main_table`.`frontend_class`, `main_table`.`source_model`, `main_table`.`is_required`, `main_table`.`is_user_defined`, `main_table`.`default_value`, `main_table`.`is_unique`, `main_table`.`note`, `additional_table`.*, IFNULL(al.value, main_table.frontend_label) AS `store_label` FROM `eav_attribute` AS `main_table`
 INNER JOIN `catalog_eav_attribute` AS `additional_table` ON additional_table.attribute_id = main_table.attribute_id
 LEFT JOIN `eav_attribute_label` AS `al` ON al.attribute_id = main_table.attribute_id AND al.store_id = 7 WHERE (main_table.entity_type_id = 4) AND (`additional_table`.`is_filterable` > 0) ORDER BY position ASC

#EDIT Add second request

2020-07-24T13:19:40+00:00 INFO (6): longueur_tasse
2020-07-24T13:19:40+00:00 INFO (6): SELECT `e`.*, `cat_index`.`position` AS `cat_index_position`, `price_index`.`price`, `price_index`.`tax_class_id`, `price_index`.`final_price`, IF(price_index.tier_price IS NOT NULL, LEAST(price_index.min_price, price_index.tier_price), price_index.min_price) AS `minimal_price`, `price_index`.`min_price`, `price_index`.`max_price`, `price_index`.`tier_price`, `stock_status_index`.`is_salable` FROM `catalog_product_entity` AS `e`
 INNER JOIN `catalog_category_product_index_store7` AS `cat_index` ON cat_index.product_id=e.entity_id AND cat_index.store_id=7 AND cat_index.visibility IN(2, 4) AND cat_index.category_id=43
 INNER JOIN `catalog_product_index_price` AS `price_index` ON price_index.entity_id = e.entity_id AND price_index.website_id = '8' AND price_index.customer_group_id = 0
 INNER JOIN `catalog_product_entity` AS `product` ON product.entity_id = e.entity_id
 INNER JOIN `inventory_stock_8` AS `stock_status_index` ON product.sku = stock_status_index.sku
 INNER JOIN `search_tmp_5f1adfebb39791_19171320` AS `search_result` ON e.entity_id = search_result.entity_id ORDER BY `cat_index`.`position` asc, `e`.`entity_id` DESC, `cat_index`.`position` asc
 LIMIT 10

2020-07-24T13:19:40+00:00 INFO (6): longueur_tasse_vertuo
2020-07-24T13:19:40+00:00 INFO (6): SELECT `e`.*, `cat_index`.`position` AS `cat_index_position`, `price_index`.`price`, `price_index`.`tax_class_id`, `price_index`.`final_price`, IF(price_index.tier_price IS NOT NULL, LEAST(price_index.min_price, price_index.tier_price), price_index.min_price) AS `minimal_price`, `price_index`.`min_price`, `price_index`.`max_price`, `price_index`.`tier_price`, `stock_status_index`.`is_salable` FROM `catalog_product_entity` AS `e`
 INNER JOIN `catalog_category_product_index_store7` AS `cat_index` ON cat_index.product_id=e.entity_id AND cat_index.store_id=7 AND cat_index.visibility IN(2, 4) AND cat_index.category_id=43
 INNER JOIN `catalog_product_index_price` AS `price_index` ON price_index.entity_id = e.entity_id AND price_index.website_id = '8' AND price_index.customer_group_id = 0
 INNER JOIN `catalog_product_entity` AS `product` ON product.entity_id = e.entity_id
 INNER JOIN `inventory_stock_8` AS `stock_status_index` ON product.sku = stock_status_index.sku
 INNER JOIN `search_tmp_5f1adfebb39791_19171320` AS `search_result` ON e.entity_id = search_result.entity_id ORDER BY `cat_index`.`position` asc, `e`.`entity_id` DESC, `cat_index`.`position` asc
 LIMIT 10

EDIT 18/08 :

I’ve been finding the class responsible for the missing data
It’s MagentoFrameworkSearchAdapterMysqlAggregationBuilder

And here is the method

public function build(
    DataProviderInterface $dataProvider,
    array $dimensions,
    RequestBucketInterface $bucket,
    Table $entityIdsTable
) {
    $metrics = $this->metricsBuilder->build($bucket);

    $select = $dataProvider->getDataSet($bucket, $dimensions, $entityIdsTable);
    $select->columns($metrics);
    $select->group(RequestBucketInterface::FIELD_VALUE);

    if($bucket->getName() === 'longueur_tasse_vertuo_bucket' || $bucket->getName() === 'longueur_tasse_bucket'){
        var_dump($bucket->getName());
        var_dump($dataProvider->execute($select));
    }
    return $dataProvider->execute($select);
}

With longueur_tasse_bucket I’ll have the result while with longueur_tasse_vertuo_bucket I won’t have anything

protected function _getIndexableAttributes($multiSelect)
{
    $select = $this->getConnection()->select()->from(
        ['ca' => $this->getTable('catalog_eav_attribute')],
        'attribute_id'
    )->join(
        ['ea' => $this->getTable('eav_attribute')],
        'ca.attribute_id = ea.attribute_id',
        []
    )->where(
        $this->_getIndexableAttributesCondition()
    );

    if ($multiSelect == true) {
        $select->where('ea.backend_type = ?', 'varchar')->where('ea.frontend_input = ?', 'multiselect');
    } else {
        $select->where('ea.backend_type = ?', 'int')->where('ea.frontend_input IN( ? )', ['select', 'boolean']);
    }
    return $this->getConnection()->fetchCol($select);
}

$writer = new ZendLogWriterStream(BP . '/var/log/layerdebug.log');
$logger = new ZendLogLogger();
$logger->addWriter($writer);
$logger->info($collection->getSelect()->__toString());

SELECT `main_table`.`entity_type_id`, `main_table`.`attribute_code`, `main_table`.`attribute_model`, `main_table`.`backend_model`, `main_table`.`backend_type`, `main_table`.`backend_table`, `main_table`.`frontend_model`, `main_table`.`frontend_input`, `main_table`.`frontend_label`, `main_table`.`frontend_class`, `main_table`.`source_model`, `main_table`.`is_required`, `main_table`.`is_user_defined`, `main_table`.`default_value`, `main_table`.`is_unique`, `main_table`.`note`, `additional_table`.*, IFNULL(al.value, main_table.frontend_label) AS `store_label` FROM `eav_attribute` AS `main_table`
 INNER JOIN `catalog_eav_attribute` AS `additional_table` ON additional_table.attribute_id = main_table.attribute_id
 LEFT JOIN `eav_attribute_label` AS `al` ON al.attribute_id = main_table.attribute_id AND al.store_id = 1 WHERE (main_table.entity_type_id = 4) AND (`additional_table`.`is_filterable` > 0)

$isAttributeFilterable =
            $this->getAttributeIsFilterable($attribute) === static::ATTRIBUTE_OPTIONS_ONLY_WITH_RESULTS;



$writer = new ZendLogWriterStream(BP . '/var/log/layerdebug.log');
    $logger = new ZendLogLogger();
    $logger->addWriter($writer);
    $logger->info($productCollection->getSelect()->__toString());