neo4j cypher collect issue

output.json

// start CategoryRoot=node(258) match CategoryRoot<-[:model_type]-Category<-[:InstrumentCategorization]-Instrument return Category, collect(Instrument)


{
    "data": [
        [{
            "outgoing_relationships": "http://localhost:7477/db/data/node/259/relationships/out",
            "data": {
                "name_en": "Wind instruments",
                "architect4r_type": "InstrumentCategory",
                "name_de": "Blasinstrumente"
            },
            "traverse": "http://localhost:7477/db/data/node/259/traverse/{returnType}",
            "all_typed_relationships": "http://localhost:7477/db/data/node/259/relationships/all/{-list|&|types}",
            "property": "http://localhost:7477/db/data/node/259/properties/{key}",
            "self": "http://localhost:7477/db/data/node/259",
            "properties": "http://localhost:7477/db/data/node/259/properties",
            "outgoing_typed_relationships": "http://localhost:7477/db/data/node/259/relationships/out/{-list|&|types}",
            "incoming_relationships": "http://localhost:7477/db/data/node/259/relationships/in",
            "extensions": {},
            "create_relationship": "http://localhost:7477/db/data/node/259/relationships",
            "paged_traverse": "http://localhost:7477/db/data/node/259/paged/traverse/{returnType}{?pageSize,leaseTime}",
            "all_relationships": "http://localhost:7477/db/data/node/259/relationships/all",
            "incoming_typed_relationships": "http://localhost:7477/db/data/node/259/relationships/in/{-list|&|types}"
        }, "[Node[256], Node[257]]"],
        [{
            "outgoing_relationships": "http://localhost:7477/db/data/node/262/relationships/out",
            "data": {
                "name_en": "Keyboard instruments",
                "architect4r_type": "InstrumentCategory",
                "name_de": "Tasteninstrumente"
            },
            "traverse": "http://localhost:7477/db/data/node/262/traverse/{returnType}",
            "all_typed_relationships": "http://localhost:7477/db/data/node/262/relationships/all/{-list|&|types}",
            "property": "http://localhost:7477/db/data/node/262/properties/{key}",
            "self": "http://localhost:7477/db/data/node/262",
            "properties": "http://localhost:7477/db/data/node/262/properties",
            "outgoing_typed_relationships": "http://localhost:7477/db/data/node/262/relationships/out/{-list|&|types}",
            "incoming_relationships": "http://localhost:7477/db/data/node/262/relationships/in",
            "extensions": {},
            "create_relationship": "http://localhost:7477/db/data/node/262/relationships",
            "paged_traverse": "http://localhost:7477/db/data/node/262/paged/traverse/{returnType}{?pageSize,leaseTime}",
            "all_relationships": "http://localhost:7477/db/data/node/262/relationships/all",
            "incoming_typed_relationships": "http://localhost:7477/db/data/node/262/relationships/in/{-list|&|types}"
        }, "[Node[265], Node[255]]"]
    ],
    "columns": ["Category", "collect(Instrument)"]
}

What version of Neo4j server are you on? Just did a test and get back (same query) with setup "Category1 model_type Root", "Violin InstrumentCategorization Category1", "Trumpet InstrumentCategorization Category1"

{
"data" : [ [ {
"outgoing_relationships" : "http://localhost:7474/db/data/node/3/relationships/out",
"data" : {
"name" : "Category1"
},
"traverse" : "http://localhost:7474/db/data/node/3/traverse/{returnType}",
"all_typed_relationships" : "http://localhost:7474/db/data/node/3/relationships/all/{-list|&|types}",
"property" : "http://localhost:7474/db/data/node/3/properties/{key}",
"self" : "http://localhost:7474/db/data/node/3",
"properties" : "http://localhost:7474/db/data/node/3/properties",
"outgoing_typed_relationships" : "http://localhost:7474/db/data/node/3/relationships/out/{-list|&|types}",
"incoming_relationships" : "http://localhost:7474/db/data/node/3/relationships/in",
"extensions" : {
},
"create_relationship" : "http://localhost:7474/db/data/node/3/relationships",
"paged_traverse" : "http://localhost:7474/db/data/node/3/paged/traverse/{returnType}{?pageSize,leaseTime}",
"all_relationships" : "http://localhost:7474/db/data/node/3/relationships/all",
"incoming_typed_relationships" : "http://localhost:7474/db/data/node/3/relationships/in/{-list|&|types}"
}, [ {
"outgoing_relationships" : "http://localhost:7474/db/data/node/2/relationships/out",
"data" : {
"name" : "Violin"
},
"traverse" : "http://localhost:7474/db/data/node/2/traverse/{returnType}",
"all_typed_relationships" : "http://localhost:7474/db/data/node/2/relationships/all/{-list|&|types}",
"property" : "http://localhost:7474/db/data/node/2/properties/{key}",
"self" : "http://localhost:7474/db/data/node/2",
"properties" : "http://localhost:7474/db/data/node/2/properties",
"outgoing_typed_relationships" : "http://localhost:7474/db/data/node/2/relationships/out/{-list|&|types}",
"incoming_relationships" : "http://localhost:7474/db/data/node/2/relationships/in",
"extensions" : {
},
"create_relationship" : "http://localhost:7474/db/data/node/2/relationships",
"paged_traverse" : "http://localhost:7474/db/data/node/2/paged/traverse/{returnType}{?pageSize,leaseTime}",
"all_relationships" : "http://localhost:7474/db/data/node/2/relationships/all",
"incoming_typed_relationships" : "http://localhost:7474/db/data/node/2/relationships/in/{-list|&|types}"
}, {
"outgoing_relationships" : "http://localhost:7474/db/data/node/1/relationships/out",
"data" : {
"name" : "Trumpet"
},
"traverse" : "http://localhost:7474/db/data/node/1/traverse/{returnType}",
"all_typed_relationships" : "http://localhost:7474/db/data/node/1/relationships/all/{-list|&|types}",
"property" : "http://localhost:7474/db/data/node/1/properties/{key}",
"self" : "http://localhost:7474/db/data/node/1",
"properties" : "http://localhost:7474/db/data/node/1/properties",
"outgoing_typed_relationships" : "http://localhost:7474/db/data/node/1/relationships/out/{-list|&|types}",
"incoming_relationships" : "http://localhost:7474/db/data/node/1/relationships/in",
"extensions" : {
},
"create_relationship" : "http://localhost:7474/db/data/node/1/relationships",
"paged_traverse" : "http://localhost:7474/db/data/node/1/paged/traverse/{returnType}{?pageSize,leaseTime}",
"all_relationships" : "http://localhost:7474/db/data/node/1/relationships/all",
"incoming_typed_relationships" : "http://localhost:7474/db/data/node/1/relationships/in/{-list|&|types}"
} ] ] ],
"columns" : [ "Category", "collect(Instrument)" ]
}