When setting FacetOrder to alphabetically, facets' content is not ordered properly when a term starts with an accented character (e.g. Études ... would be placed at the end and not under 'E'), both with Zebra and with Elasticsearch. `use locale` (in C4/Search.pm and be a solution Koha/SearchEngine/Elasticsearch/Search.pm) seems to solve the issue.
*** This bug has been marked as a duplicate of bug 36947 ***