Facet summary output issue on AJAX

Module version installed is 8.x.1.6

Problem/Motivation

When you enable the Facets summary and click on some of the facets you get an error.

TypeError: Argument 2 passed to Drupal\Core\Link::__construct() must be an instance of Drupal\Core\Url, null given, called in /web/modules/contrib/facets/modules/facets_summary/src/FacetsSummaryManager/DefaultFacetsSummaryManager.php on line 166 in Drupal\Core\Link->__construct() (line 40 of core/lib/Drupal/Core/Link.php).

I noticed that function buildResultTree within DefaultFacetsSummaryManager is called twice in less than a second. First time URL is set to null, on second time URL is correct Drupal URL object.

Steps to reproduce

• Create a search index view and enable ajax use.
• Create facets with taxonomy them.
• Create facet summary
• Filter by term

This error actually breaks the view from being refreshed on ajax.

If you reload the page, active facets are added to summary and view gets refreshed.

I also noticed that Drupal.Ajax.prototype.beforeSend within facets-views-ajax.js file is called twice, with probably cause this issue.

https://www.drupal.org/files/issues/2020-10-02/facets-ajax-3052574-89.patch → -> This patch has been already applied.