ZF3 - Zend\Db\Sql\Predicate\Expression - Wrong escaping on SQL DATE_FORMAT

I'm trying to filter a radius accounting database based on the submitted session start time. The field "acctstartime" is defined as DATETIME in the MySQL database.

This is the working SQL query I'd like to build:

SELECT * FROM radacct WHERE DATE_FORMAT(acctstarttime, '%Y-%m-%d') = DATE_FORMAT('2019-08-10' , '%Y-%m-%d') ORDER BY "radacctid" DESC LIMIT 100

In my ZF3-Controller, I'm building the SQL-query based on the submitted parameters using the Zend\Db abstraction layer. But unforunately the Db layer escapes the %-Signs and produces a SQL-string which is not working:

SELECT * FROM radacct WHERE DATE_FORMAT(acctstarttime, '%%Y-%%m-%%d') = DATE_FORMAT('2019-01-01' , '%%Y-%%m-%%d') AND "acctstarttime" = '2019-01-01' ORDER BY "radacctid" DESC LIMIT 100

In the file zend-db/src/Sql/Expression.php on line 136:

$expression = str_replace('%', '%%', $this->expression);

Has anybody a clue how to generate the query above? Or maybe another way to do the same thing? I haven't found any workaround for this type of expression using DATE_TIME.

---

The controller:

class AccountingController extends AbstractRestfulJsonController {
    protected $service;

    public function __construct(RadiusService $service) {
        $this->service = $service;
    }

    public function get($id) {
        return $this->getList();
    }

    public function getList() {
        $viewModel = new JsonModel();

        try {
            $filter = [];
            $paramsRoute = $this->params()->fromRoute();
            $paramsQuery = $this->params()->fromQuery();
            $params = (OBJECT) array_merge($paramsRoute, $paramsQuery);

            if(isset($params->id)) {
                $filter['radacctid'] = (int) $params->id;
            }

            // ...

            if(isset($params->sessionStartTime) && strlen($params->sessionStartTime) > 0) {
                $filter[] = new Expression("DATE_FORMAT(acctstarttime, '%Y-%m-%d') = DATE_FORMAT('" . $params->sessionStartTime . "' , '%Y-%m-%d')");
            }

            // ...

            $data = $this->service->getAccounting($filter);

            $viewModel->setVariable('state', 'ok');
            $viewModel->setVariable('count', $data['totalItems']);
            $viewModel->setVariable('data', $data['items']);
        } catch (\Exception $e) {
            $viewModel->setVariable('state', 'nok');
            $viewModel->setVariable('message', $e->getMessage());
        }

        return $viewModel;
    }
}

so what about "SUBSTRING(acctstarttime, 1, 10) = '". substr($params->sessionStartTime, 0, 10) . "'" ?