I had to do something insane to find a work around. We were initializing the kendo drop down list in asp/razor and not with javascript/jquery. I couldn't find an equivalent for:

valuePrimitive: true

So, i instead converted all null values in the result set for the field in question to spaces and that worked:

var result = _dbContext.EsFleetAuto.Where(es => es.FkSurveyId == SurveyId).OrderBy(x => x.LicensePlate);

foreach (var item in result)
{
    if (string.IsNullOrEmpty(item.AutoType))
        item.AutoType = "";
}