diff --git a/lib/Service/SubmissionService.php b/lib/Service/SubmissionService.php
index 8df23779b..42c3bb1ce 100644
--- a/lib/Service/SubmissionService.php
+++ b/lib/Service/SubmissionService.php
@@ -207,7 +207,7 @@ public function getSubmissionsData(Form $form, string $fileFormat, ?File $file =
 		$submissionEntities = array_reverse($submissionEntities);
 
 		$questions = $this->questionMapper->findByForm($form->getId());
-		$defaultTimeZone = date_default_timezone_get();
+		$defaultTimeZone = $this->config->getSystemValueString('default_timezone', 'UTC');
 
 		if (!$this->currentUser) {
 			$userTimezone = $this->config->getUserValue($form->getOwnerId(), 'core', 'timezone', $defaultTimeZone);
diff --git a/tests/Unit/Service/SubmissionServiceTest.php b/tests/Unit/Service/SubmissionServiceTest.php
index 07f71e2a3..55ac37d76 100644
--- a/tests/Unit/Service/SubmissionServiceTest.php
+++ b/tests/Unit/Service/SubmissionServiceTest.php
@@ -579,7 +579,11 @@ private function setUpCsvTest(array $questions, array $submissions, string $csvT
 				return $questionEntities;
 			}));
 
-		date_default_timezone_set('Europe/Berlin');
+		$this->config->expects($this->once())
+			->method('getSystemValueString')
+			->with('default_timezone', 'UTC')
+			->willReturn('Europe/Berlin');
+
 		$this->config->expects($this->once())
 			->method('getUserValue')
 			->with('currentUser', 'core', 'timezone', 'Europe/Berlin')