Visual merchandiser changes do not trigger a purge of varnish

[JamesAllwood]

When Magento is configured to use Varnish as FPC, using the visual merchandiser to reorder pinned products, while having indexers set to schedule, does not trigger a purge of cache for the affected category after the indexer has completed the backlog of saved items

If the category is not visited until after the indexer has completed running, the correct results are shown, which indicates that perhaps varnish is being flushed, but before the indexer has completed. (in a production store, many users are accessing the category during the time that the indexer is running)

Without Smile installed, and using Magento's sort for products in a category, it's also noted that the issue can not be replicated, and also that when adjusting positions, additional _cl tables are updated so that catalogrule_product, catalogsearch_fulltext, and catalog_product_category are queued up. I assume that catalog_product_category is likely responsible for purging affected caches after completing

Preconditions

Magento Version : 2.4.6-p6

ElasticSuite Version : 2.11.7.1

Environment : Production

Third party modules : None (tested on a vanilla install to ensure no 3rd party influence)

Steps to reproduce

1. Configure Magento to use Varnish as FPC and ensure that the category page you're testing is responding in < 100ms to confirm that you're viewing a varnish page
2. Set all indexers to run on schedule
3. On a given category, set a number of products to be pinned and save the category
4. Once reloaded, manually drag and drop the products to new positions and save the category
5. Observe the indexer shows a number of queued items in catalogsearch_fulltext
6. Keep refreshing the category on the frontend to check the positions

Expected result

1. After indexing has completed, positions should update on the frontend to match those in the admin

Actual result

1. Positions on the frontend are not updated