Unable to pass aws.events.event.json in input transformer template

I am using eventbridge to trigger batch run through custom put-events request(using boto3). My request is as follows :-

INPUT_DATA = {
    "data":[List<Dict>], # i.e. data key has list value where each list item is dict
    "sample_key":"sample_string_value"
}
client = boto3.client("events")
response = client.put_events(Entries=[
    {
        "Source": "my.app.com",
        "Detail": json.dumps(INPUT_DATA),
        "DetailType":"sample-type",
        "EventBusName":"my-event-bus"
    }
])

In order to pass data from eventbridge to batch, I have following input transformer template :-

input_paths = {
}

input_template = <<EOF
{
  "ContainerOverrides": {
    "Environment": [
      {
        "Name": "PAYLOAD",
        "Value": "<aws.events.event.json>"
      }
    ]
  }
}
EOF

where aws.events.event.json is pre-defined variable for event payload(i.e. detail key value) as string.

When I run the script, I am able to see metric for triggeredRulewith 1 but invocation for batch run fails i.e. failedInvocations count as 1 is also seen in the metrics. At the same time, if replace aws.events.event.json with aws.events.rule-arn or aws.events.rule-name or aws.events.event.ingestion-time, batch run is triggered and correct values of latter variables is also seen in job descriptions's environment section.

I tried to refer similar issue here but it does not seem solve the issue.

Can someone suggest where is the issue in above input transformer while using aws.events.event.json ? Is it due format of INPUT_DATA that I am sending ? Would appreciate any hint.

Thanks