Wave - Unable to bind date filter to a step using different dataset

Question

In Wave, I have been unsuccessful in performing cross-dataset filtering.

I have a target step (chart widget) that is connected to one dataset that I'd like to filter by the date selected in another step that is connected to a different dataset.

I'm using a selection binding and attempting to bind using the compact format and not the SAQL(pigql) format.

Here's the warning I get on the widget when I try to select a different date:

This widget can't be displayed because there is a problem with its
source step:
   Cannot read property '0' of null

Does anyone have an idea of what I might be missing?

Thanks.

Below is a snippet of the JSON that I have:

Source (date) step:

"TradeCreateDate__c_Y_1": {
    "datasets": [
        {
        ...snip...
        }
    ],
    "isFacet": true,
    "isGlobal": false,
    "label": "",
    "query": {
        "measures": [
            [
                "count",
                "*"
            ]
        ],
        "groups": [
            "TradeCreateDate__c_Year"
        ]
    },
    "selectMode": "single",
    "type": "aggregateflex",
    "useGlobal": false,
    "visualizationParameters": {
        "options": {}
    }
},

Target step:

"prod_by_strat_1": {
    "datasets": [
        {
            ...snip...
        }
    ],
    "isFacet": true,
    "isGlobal": false,
    "label": "prod by strat",
    "query": {
        "measures": [
            [
                "sum",
                "TradeAmount__c"
            ]
        ],
        "groups": [
            "Test_Mo.StrategistName"
        ],
        "filters": [
           ...snip...
            <b>[
                "TradeCreateDate__c",
                "{{row(TradeCreateDate__c_Y_1.selection, [0], [\"min\",\"max\"]).asObject()}}"
            ]</b>
        ],
        "order": [
            [
                -1,
                {
                    "ascending": false
                }
            ]
        ]
    },
    "selectMode": "single",
    "type": "aggregateflex",
    "useGlobal": true,
    "visualizationParameters": {
        "visualizationType": "hbar",
        "options": {}
    }
}