rejected records error

I am recieving the following error when trying to test a lambda function to write to timestream:

RejectedRecords:  An error occurred (RejectedRecordsException) when calling the WriteRecords operation: One or more records have been rejected. See RejectedRecords for details.
Rejected Index 0: Multi measure name already has an assigned measure value type. Each multi measure name can have only one measure value type and cannot be changed.
Other records were written successfully. 

This is the code for my 'records' array:

    records = [{
    'Dimensions': dimensions,
    'Time': CURRENT_TIME,
    'MeasureName': 'measurementvalues',
    'MeasureValueType': 'MULTI',
    'MeasureValues': [
    {'Name': 'rainfall_mm', 'Value': str(event["rain_mm"]), 'Type': 'DOUBLE'},
    {'Name': 'Temperature', 'Value': str(event["temperature_C"]), 'Type': 'DOUBLE'},
    {'Name': 'humidity', 'Value': str(event["humidity"]), 'Type': 'BIGINT'},
    {'Name': 'wind_max_m_s', 'Value': str(event["wind_max_m_s"]), 'Type': 'DOUBLE'},
    {'Name': 'wind_avg_m_s', 'Value': str(event["wind_avg_m_s"]), 'Type': 'DOUBLE'},
    {'Name': 'wind_dir_deg', 'Value': str(event["wind_dir_deg"]), 'Type': 'DOUBLE'},
    {'Name': 'Battery_check', 'Value': str(event["battery_ok"]), 'Type': 'BIGINT'},
    {'Name': 'wind_max_mph', 'Value':str(event["wind_max_m_s"]*2.23694), 'Type':'DOUBLE'},
    {'Name': 'wind_avg_mph', 'Value':str(event["wind_avg_m_s"]*2.23694), 'Type':'DOUBLE'},
    {'Name': 'wind_dir_deg_corr', 'Value':str(event["wind_dir_deg"]+0), 'Type':'DOUBLE'},
    ]
    }, ]

I would be very grateful if anyone could shed light on this error :)