label-studio: Prepopulating relations among entities for NER annotation doesn't work

Describe the bug

I’m using LabelStudio for a NER + Relations Among Entities task.

I want to pre-populate some relations to the annotation (using predictions). When I pre-populate entities, it shows up fine. However, when I try to pre-populate relations, I get the following error in my browser console:

Uncaught (in promise) Error: [mobx-state-tree] Can only store references to tree nodes or identifiers, got: 'undefined'
    at be (mobx-state-tree.module.js:3662)
    at new e (mobx-state-tree.module.js:6984)
    at t.instantiate (mobx-state-tree.module.js:7243)
    at mobx-state-tree.module.js:5734
    at mobx-state-tree.module.js:5891
    at Array.forEach (<anonymous>)
    at t.forAllProps (mobx-state-tree.module.js:5890)
    at t.initializeChildNodes (mobx-state-tree.module.js:5733)
    at new t (mobx-state-tree.module.js:1442)
    at ae (mobx-state-tree.module.js:3401)

Also, the spinner keeps spinning and nothing shows up in my browser.

This is the content of my tasks.json:

[
    {
        "id": 2,
        "data": {
            "text": "sales rep with highest sales for winkle"
        },
        "predictions": [
            {
                "result": [
                    {
                        "id": "anJaSFkP",
                        "from_name": "label",
                        "to_name": "text",
                        "type": "labels",
                        "normalization": "1P sales (Local Currency)",
                        "value": {
                            "start": 23,
                            "end": 28,
                            "text": "sales",
                            "labels": [
                                "Measure"
                            ]
                        }
                    },
                    {
                        "id": "pBUYX3sZ",
                        "from_name": "label",
                        "to_name": "text",
                        "type": "labels",
                        "normalization": "Sales Representative",
                        "value": {
                            "start": 0,
                            "end": 9,
                            "text": "sales rep",
                            "labels": [
                                "Attribute"
                            ]
                        }
                    },
                    {
                        "id": "L7o4xpaW",
                        "from_name": "label",
                        "to_name": "text",
                        "type": "labels",
                        "normalization": "Winkle~~Brand",
                        "value": {
                            "start": 33,
                            "end": 39,
                            "text": "winkle",
                            "labels": [
                                "Business Object"
                            ]
                        }
                    },
                    {
                        "id": "TV7255ne",
                        "from_name": "label",
                        "to_name": "text",
                        "type": "labels",
                        "normalization": "TOP 1",
                        "value": {
                            "start": 15,
                            "end": 22,
                            "text": "highest",
                            "labels": [
                                "Rank"
                            ]
                        }
                    },
                    /* THE RELATIONS BELOW IS THE PROBLEM */
                    {
                        "direction": "right",
                        "from_id": "TV7255ne",
                        "labels": [
                            "Rank-Attribute"
                        ],
                        "to_id": "pBUYX3sZ",
                        "type": "relation"
                    },
                    {
                        "direction": "right",
                        "from_id": "TV7255ne",
                        "labels": [
                            "Rank-Measure"
                        ],
                        "to_id": "anJaSFkP",
                        "type": "relation"
                    }
                ]
            }
        ]
    },
]

This is the content of my config.xml:

<View>

  <Relations>
    <Relation value="Period-Measure" />
    <Relation value="Measure-Condition" />
    <Relation value="Rank-Attribute" />
    <Relation value="Rank-Periodicity" />
    <Relation value="Rank-Attribute (Group)" />
    <Relation value="Rank-Periodicity (Group)" />
    <Relation value="Rank-Measure" />
  </Relations>

  <Labels name="label" toName="text">
    <Label value="Measure" />
    <Label value="Business Object" />
    <Label value="Attribute" />
    <Label value="Periodicity (Global)" />
    <Label value="Periodicity (Rank)" />
    <Label value="Temporal (Specific)" />
    <Label value="Temporal (Range)" />
    <Label value="Range (Start)" />
    <Label value="Range (End)" />
    <Label value="Condition Type" />
    <Label value="Condition Value" />
    <Label value="Rank" />
  </Labels>

  <Text name="text" value="$text" />

</View>

P.S. When I annotate the relation manually myself, the resulting JSON for that relation (in the completions folder is identical to what I have in the predictions list).