Nope, unfortunately, tests don't confirm it.
Meanwhile, investigation in prod shows that specifying a correct partition number also returns empty result, ie:
curl -X POST http://$1/druid/v2 -d'{
"queryType": "timeseries",
"dataSource": "'$2'",
"granularity": "hour",
"intervals": {
"type": "segments",
"segments": [
{
"itvl":"2018-09-28T00:00:00.000Z/2018-09-28T01:00:00.000Z",
"ver":"'$3'",
"part": '$4'
}
]
},
"aggregations": [
{ "type" : "count", "name" : "count" }
],
"metric": "count"
}' -H "Content-type: application/json"
Still, it works for some other datasources, I checked that ShardSpec type is the same (hashed).