Querying suggester with alias fails

There's a problem using a multi-collection alias in combination with suggester request. We used version 7.3.1 and had no problems, after upgrading to version 8.x exceptions are thrown.

Details

I created an alias called „WORLD“ pointing to six collections.

// aliases.json
{"collection":{
    "AT":"AT.test",
    "BE":"BE.test",
    "DE":"DE.test",
    "FR":"FR.test",
    "LU":"LU.test",
    "NL":"NL.test",
    "WORLD":"AT.test,BE.test,DE.test,FR.test,LU.test,NL.test"}
}

If I send a /suggest request using SolrJClient with "WORLD" I get the error message: „No live SolrServers available to handle this request:[http://[myIP]:8983/solr/WORLD“.

If I try to call /suggest via Solr HTTP API, I get „Timeout occured while waiting response from server at: http://[myIP]:8983/solr/AT.test_shard1_replica_n1/suggest“ (see full stacktrace attached). The collection name within the error messages differs (AT.test... or BE.test... ) but the error information is still the same.

// HTTP API Suggester Call
http://[myIP]:8983/solr/WORLD/suggest?suggest=true&suggest.q=Rue%20Roi%20Albert&suggest.dictionary=streetSuggester&suggest.dictionary=streetSuggesterFuzzy&suggest.build=true

 If I use single-collection Aliases (e.g. "AT") everything works fine.