diff --git a/lib/taskana-core/src/main/java/pro/taskana/impl/ClassificationServiceImpl.java b/lib/taskana-core/src/main/java/pro/taskana/impl/ClassificationServiceImpl.java
index d62dd2e44..c01bf059e 100644
--- a/lib/taskana-core/src/main/java/pro/taskana/impl/ClassificationServiceImpl.java
+++ b/lib/taskana-core/src/main/java/pro/taskana/impl/ClassificationServiceImpl.java
@@ -180,7 +180,7 @@ public class ClassificationServiceImpl implements ClassificationService {
 
             // Update classification fields used by tasks
             if (oldClassification.getCategory() != classificationImpl.getCategory()) {
-                List<TaskSummary> taskSumamries = taskanaEngine.getTaskService()
+                List<TaskSummary> taskSummaries = taskanaEngine.getTaskService()
                     .createTaskQuery()
                     .classificationIdIn(oldClassification.getId())
                     .list();
@@ -188,9 +188,9 @@ public class ClassificationServiceImpl implements ClassificationService {
                 boolean categoryChanged = !(oldClassification.getCategory() == null
                     ? classification.getCategory() == null
                     : oldClassification.getCategory().equals(classification.getCategory()));
-                if (!taskSumamries.isEmpty() && categoryChanged) {
+                if (!taskSummaries.isEmpty() && categoryChanged) {
                     List<String> taskIds = new ArrayList<>();
-                    taskSumamries.stream().forEach(ts -> taskIds.add(ts.getTaskId()));
+                    taskSummaries.stream().forEach(ts -> taskIds.add(ts.getTaskId()));
                     taskMapper.updateClassificationCategoryOnChange(taskIds, classificationImpl.getCategory());
                 }
             }
@@ -262,7 +262,7 @@ public class ClassificationServiceImpl implements ClassificationService {
             classification.setIsValidInDomain(true);
         }
 
-        if (classification.getServiceLevel() != null) {
+        if (classification.getServiceLevel() != null && !"".equals(classification.getServiceLevel())) {
             try {
                 Duration.parse(classification.getServiceLevel());
             } catch (Exception e) {
diff --git a/lib/taskana-core/src/test/java/pro/taskana/impl/ClassificationServiceImplTest.java b/lib/taskana-core/src/test/java/pro/taskana/impl/ClassificationServiceImplTest.java
index 62b76cb98..f585f9548 100644
--- a/lib/taskana-core/src/test/java/pro/taskana/impl/ClassificationServiceImplTest.java
+++ b/lib/taskana-core/src/test/java/pro/taskana/impl/ClassificationServiceImplTest.java
@@ -14,7 +14,9 @@ import static org.mockito.Mockito.verifyNoMoreInteractions;
 
 import java.time.Instant;
 import java.time.LocalDate;
+import java.util.List;
 
+import org.apache.ibatis.session.SqlSession;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -31,6 +33,7 @@ import pro.taskana.exceptions.DomainNotFoundException;
 import pro.taskana.exceptions.InvalidArgumentException;
 import pro.taskana.exceptions.NotAuthorizedException;
 import pro.taskana.mappings.ClassificationMapper;
+import pro.taskana.mappings.JobMapper;
 
 /**
  * Unit Test for ClassificationServiceImpl.
@@ -55,6 +58,9 @@ public class ClassificationServiceImplTest {
     @Mock
     private ClassificationQueryImpl classificationQueryImplMock;
 
+    @Mock
+    private SqlSession sqlSessionMock;
+
     @Before
     public void setup() {
         doNothing().when(taskanaEngineImplMock).openConnection();
@@ -210,7 +216,8 @@ public class ClassificationServiceImplTest {
         classification.setParentKey("ParentKey");
         ClassificationImpl parentDomainClassification = (ClassificationImpl) createDummyClassification("ParentId");
         parentDomainClassification.setKey("ParentKey");
-        ClassificationImpl parentMasterClassification = (ClassificationImpl) createDummyClassification("ParentIdMaster");
+        ClassificationImpl parentMasterClassification = (ClassificationImpl) createDummyClassification(
+            "ParentIdMaster");
         parentMasterClassification.setKey("ParentKey");
         parentMasterClassification.setDomain("");
         doReturn(null).when(classificationMapperMock).findByKeyAndDomain(classification.getKey(),
@@ -268,6 +275,24 @@ public class ClassificationServiceImplTest {
         verifyNoMoreInteractions(classificationMapperMock, taskanaEngineImplMock, classificationQueryImplMock);
     }
 
+    @Test
+    public void testUpdateClassificationWithEmptyServiceLevel()
+        throws ClassificationNotFoundException, NotAuthorizedException, ConcurrencyException, InvalidArgumentException {
+        Instant now = Instant.now();
+        Classification classification = createDummyClassification();
+        ((ClassificationImpl) classification).setModified(now);
+        classification.setServiceLevel("");
+        ClassificationImpl oldClassification = (ClassificationImpl) createDummyClassification();
+        oldClassification.setModified(now);
+        doReturn(oldClassification).when(cutSpy).getClassification(classification.getKey(), classification.getDomain());
+        doReturn(sqlSessionMock).when(taskanaEngineImplMock).getSqlSession();
+        doReturn(new JobRunnerMock()).when(sqlSessionMock).getMapper(any());
+
+        cutSpy.updateClassification(classification);
+
+        verify(classificationMapperMock, times(1)).update(any());
+    }
+
     @Test(expected = ClassificationNotFoundException.class)
     public void testUpdateClassificationParentIdNotExisting()
         throws ClassificationNotFoundException, NotAuthorizedException,
@@ -419,4 +444,29 @@ public class ClassificationServiceImplTest {
         classificationImpl.setParentKey("");
         return classificationImpl;
     }
+    /**
+     * This is the mock of a jobRunner.
+     */
+    private class JobRunnerMock implements JobMapper {
+
+        @Override
+        public void insertJob(Job job) {
+
+        }
+
+        @Override
+        public List<Job> findJobsToRun() {
+            return null;
+        }
+
+        @Override
+        public void update(Job job) {
+
+        }
+
+        @Override
+        public void delete(Job job) {
+
+        }
+    }
 }