How can I delete item from nested array using arrayRemove? [duplicate]

Can someone tell me why this does not work:

const deleteItem = index => {
   firebase
     .firestore()
     .collection("user")
     .doc(user1)
     .update({
       Travellers : firebase.firestore.FieldValue.arrayRemove({Name: item.Travellers[index].Name, Weight: item.Travellers[index].Weight})
     })
  };

The array:

[
    {
        "id": "rWFZhAKk9eOSIIFoP0DqqvrC6WJ3",
        "Travellers": [
            {
                "Name": "Mike",
                "Weight": "100.00"
            },
            {
                "Name": "Bob",
                "Weight": "95.00"
            }
        ]
    }
]

The code works fine for arrayUnion when adding to this array, but removing it is not. If I hardcode the values into Name and Weight then it removes just fine.

Console returns (before the firebase.update) Mike and 100.00 as index 0.

Firebase screenshot: