Unexpected results using Block Join Parent Query Parser

[Tor-Magne Stien Hagen]

Hi,

I have indexed the following nested document in Solr:

{
    "id": "1",
    "class": "composition",
    "children": [
        {
            "id": "2",
            "class": "section",
            "children": [
                {
                    "id": "3",
                    "class": "observation"
                }
            ]
        },
        {
            "id": "4",
            "class": "section",
            "children": [
                {
                    "id": "5",
                    "class": "instruction"
                }
            ]
        }
    ]
}

Given the following query:

{!parent which='id:4'}id:3

I expect the result to be empty as document 3 is not a child document of 
document 4.

To reproduce, use the docker container provided here:
https://github.com/tormsh/Solr-Example

Have I misunderstood something regarding the Block Join Parent Query Parser?

Tor-Magne Stien Hagen