On a big index (60.000 documents) the autosuggests fails with a timeout. The query doesn't respond even after 10 minutes.
The Solr log shows "Too many values for UnInvertedField faceting on field suggestions" but I'm not completely sure if it is related to the query, because I did multiple queries and the log shows the error only one time.
See comments for the query / example URL.
The query also fails with different terms, also with terms which should return 0 results the query fails.