Shopware 6 Plugin - text snippet not deleted on uninstall plugin - order custom field label

Question

We created custom fields within our plugin for orders and for products. Shopware creates text snippets for the custom fields labels. These should be removed when uninstalling the plugin.

It works for the products custom field.

...
'customFields' => [
    [
        'name' => 'product_custom_field_name_dummy',
        'type' => CustomFieldTypes::BOOL,
        'config' => [
            'type' => 'checkbox',
            'componentName' => 'sw-field',
            'customFieldType' => 'checkbox',
            'label' => [
                self::GER_ISO => 'Label GER',
                self::EN_ISO => 'Label EN',
                Defaults::LANGUAGE_SYSTEM => 'Label EN',
            ]
        ],
    ]
],
'relations' => [
    [
        'entityName' => ProductDefinition::ENTITY_NAME,
    ],
],
...

But not for the orders custom fields.

...
'customFields' => [
    [
        'name' => 'order_custom_field_name_dummy_one',
        'type' => CustomFieldTypes::TEXT,
        'config' => [
            'customFieldType' => CustomFieldTypes::TEXT,
            'label' => [
                self::GER_ISO => 'Order Label GER',
                self::EN_ISO => 'Order Label EN',
                Defaults::LANGUAGE_SYSTEM => 'Order Label EN',
            ]
        ],
    ],
    [
        'name' => 'order_custom_field_name_dummy_two',
        'type' => CustomFieldTypes::SELECT,
        'config' => [
            'customFieldType' => CustomFieldTypes::SELECT,
            'componentName' => 'sw-single-select',
            'label' => [
                self::GER_ISO => 'Order Label GER 2',
                self::EN_ISO => 'Order Label EN 2',
                Defaults::LANGUAGE_SYSTEM => 'Order Label EN 2',
            ],
            'options' => [
                ...
            ]
        ]
    ],
    [
        'name' => 'order_custom_field_name_dummy_three',
        'type' => CustomFieldTypes::DATETIME,
        'config' => [
            'customFieldType' => CustomFieldTypes::DATETIME,
            'label' => [
                self::GER_ISO => 'Order Label GER 3',
                self::EN_ISO => 'Order Label EN 3',
                Defaults::LANGUAGE_SYSTEM => 'Order Label EN 3',
            ]
        ],
    ],
    [
        'name' => 'order_custom_field_name_dummy_four',
        'type' => CustomFieldTypes::SELECT,
        'config' => [
            'customFieldType' => CustomFieldTypes::SELECT,
            'componentName' => 'sw-single-select',
            'label' => [
                self::GER_ISO => 'Order Label GER 4',
                self::EN_ISO => 'Order Label EN 4',
                Defaults::LANGUAGE_SYSTEM => 'Order Label EN 4',
            ],
            'options' => [
                ...
            ]
        ],
    ],
],
'relations' => [
    [
        'entityName' => OrderDefinition::ENTITY_NAME,
    ],
],
...

Is this a problem Shopware has with order custom fields or did we possibly make a mistake when creating the order custom fields?

Edit: The custom fields are created on install method und removed on uninstall method inside the plugin via the CustomFieldSetRepository.

Edit: This is how we delete the custom fields on uninstall:

public function uninstallCustomFieldSet() {
    $customFieldSet = $this->getCustomFieldSet(self::CUSTOM_FIELD_SET_NAME);
    if ($customFieldSet instanceof CustomFieldSetEntity) {
        $this->customFieldSetRepository->delete([['id' => $customFieldSet->getId()]], $this->context);
    }
}

protected function getCustomFieldSet(string $customFieldSetName): ?CustomFieldSetEntity {
    $criteria = new Criteria();
    $criteria->addFilter(new EqualsFilter('name', $customFieldSetName));
    $criteria->addAssociation('customFields');
    $criteria->addAssociation('relations');
    $customFieldSet = $this->customFieldSetRepository->search($criteria, $this->context)->first();

    if ($customFieldSet instanceof CustomFieldSetEntity) {
        return $customFieldSet;
    } else {
        return null;
    }
}

Answer 1

The author mentions that Shopware 6 confirms that it's a bug.

I am creating an answer to this question even though it was already answered in the comments so that it can be accepted & this question resolved.