Elixir package - Filters

I’m trying to do a facet filter query on one of my idices. The facet is setup as taxons.id and I can successfully make query filters on it in the Algolia index browser.

My code is using the Elixir package to query Algolia.
Here is what it looks like:
Algolia.search("my_cool_index", "batman", [{"attributesToRetrieve", "product_id"},{"filters", "taxons.id:26"},{"hitsPerPage", 2}])

Here is what I get back from Algolia:

   "exhaustiveNbHits" => true,
   "hits" => [],
   "hitsPerPage" => 2,
   "ids" => [],
   "nbHits" => 0,
   "nbPages" => 0,
   "page" => 0,
   "params" => "query=batman&attributesToRetrieve=product_id&filters=taxons.id%3A26&hitsPerPage=2",
   "processingTimeMS" => 1,
   "query" => "batman"

It seems like the filter is done properly, but it yields no results. On the browser for the same exact query and same index, I get results…
Any idea of what I could be doing wrong?

Side note: I also tried with facetFilters=[["taxons.id:26"]] but to no avail …