diff --git a/common/persistence/src/main/java/app/coronawarn/server/common/persistence/repository/DiagnosisKeyRepository.java b/common/persistence/src/main/java/app/coronawarn/server/common/persistence/repository/DiagnosisKeyRepository.java
index cfec2bc6ef..22bdf9dedb 100644
--- a/common/persistence/src/main/java/app/coronawarn/server/common/persistence/repository/DiagnosisKeyRepository.java
+++ b/common/persistence/src/main/java/app/coronawarn/server/common/persistence/repository/DiagnosisKeyRepository.java
@@ -36,8 +36,8 @@ public interface DiagnosisKeyRepository extends PagingAndSortingRepository<Diagn
    * @param submissionTimestamp The submission timestamp up to which entries will be expired.
    * @return The number of expired keys.
    */
-  @Query("SELECT COUNT(*) FROM diagnosis_key WHERE submission_timestamp<=:threshold")
-  int countOlderThanOrEqual(@Param("threshold") long submissionTimestamp);
+  @Query("SELECT COUNT(*) FROM diagnosis_key WHERE submission_timestamp<:threshold")
+  int countOlderThan(@Param("threshold") long submissionTimestamp);
 
   /**
    * Deletes all entries that have a submission timestamp less or equal than the specified one.
@@ -45,8 +45,8 @@ public interface DiagnosisKeyRepository extends PagingAndSortingRepository<Diagn
    * @param submissionTimestamp The submission timestamp up to which entries will be deleted.
    */
   @Modifying
-  @Query("DELETE FROM diagnosis_key WHERE submission_timestamp<=:threshold")
-  void deleteOlderThanOrEqual(@Param("threshold") long submissionTimestamp);
+  @Query("DELETE FROM diagnosis_key WHERE submission_timestamp<:threshold")
+  void deleteOlderThan(@Param("threshold") long submissionTimestamp);
 
   /**
    * Attempts to write the specified diagnosis key information into the database. If a row with the specified key data
diff --git a/common/persistence/src/main/java/app/coronawarn/server/common/persistence/service/DiagnosisKeyService.java b/common/persistence/src/main/java/app/coronawarn/server/common/persistence/service/DiagnosisKeyService.java
index 6eabe3f4ed..2edddb0c44 100644
--- a/common/persistence/src/main/java/app/coronawarn/server/common/persistence/service/DiagnosisKeyService.java
+++ b/common/persistence/src/main/java/app/coronawarn/server/common/persistence/service/DiagnosisKeyService.java
@@ -113,9 +113,9 @@ public void applyRetentionPolicy(int daysToRetain) {
         .ofInstant(Instant.now(), UTC)
         .minusDays(daysToRetain)
         .toEpochSecond(UTC) / SECONDS_PER_HOUR;
-    int numberOfDeletions = keyRepository.countOlderThanOrEqual(threshold);
+    int numberOfDeletions = keyRepository.countOlderThan(threshold);
     logger.info("Deleting {} diagnosis key(s) with a submission timestamp older than {} day(s) ago.",
         numberOfDeletions, daysToRetain);
-    keyRepository.deleteOlderThanOrEqual(threshold);
+    keyRepository.deleteOlderThan(threshold);
   }
 }
diff --git a/common/persistence/src/test/java/app/coronawarn/server/common/persistence/service/DiagnosisKeyServiceTest.java b/common/persistence/src/test/java/app/coronawarn/server/common/persistence/service/DiagnosisKeyServiceTest.java
index 46183f08bd..4ef3149432 100644
--- a/common/persistence/src/test/java/app/coronawarn/server/common/persistence/service/DiagnosisKeyServiceTest.java
+++ b/common/persistence/src/test/java/app/coronawarn/server/common/persistence/service/DiagnosisKeyServiceTest.java
@@ -114,7 +114,7 @@ void testApplyRetentionPolicyForEmptyDb() {
 
   @Test
   void testApplyRetentionPolicyForOneNotApplicableEntry() {
-    var expKeys = List.of(buildDiagnosisKeyForDateTime(OffsetDateTime.now(UTC).minusHours(23)));
+    var expKeys = List.of(buildDiagnosisKeyForDateTime(OffsetDateTime.now(UTC).minusDays(1L)));
 
     diagnosisKeyService.saveDiagnosisKeys(expKeys);
     diagnosisKeyService.applyRetentionPolicy(1);
@@ -125,7 +125,7 @@ void testApplyRetentionPolicyForOneNotApplicableEntry() {
 
   @Test
   void testApplyRetentionPolicyForOneApplicableEntry() {
-    var keys = List.of(buildDiagnosisKeyForDateTime(OffsetDateTime.now(UTC).minusDays(1L)));
+    var keys = List.of(buildDiagnosisKeyForDateTime(OffsetDateTime.now(UTC).minusDays(1L).minusHours(1)));
 
     diagnosisKeyService.saveDiagnosisKeys(keys);
     diagnosisKeyService.applyRetentionPolicy(1);
diff --git a/services/distribution/src/main/java/app/coronawarn/server/services/distribution/runner/TestDataGeneration.java b/services/distribution/src/main/java/app/coronawarn/server/services/distribution/runner/TestDataGeneration.java
index 79b31f812e..c90e29b020 100644
--- a/services/distribution/src/main/java/app/coronawarn/server/services/distribution/runner/TestDataGeneration.java
+++ b/services/distribution/src/main/java/app/coronawarn/server/services/distribution/runner/TestDataGeneration.java
@@ -98,7 +98,7 @@ private void writeTestData() {
 
     // Timestamps in hours since epoch. Test data generation starts one hour after the latest diagnosis key in the
     // database and ends one hour before the current one.
-    long startTimestamp = getGeneratorStartTimestamp(existingDiagnosisKeys) + 1; // Inclusive
+    long startTimestamp = getGeneratorStartTimestamp(existingDiagnosisKeys); // Inclusive
     long endTimestamp = getGeneratorEndTimestamp(); // Inclusive
 
     // Add the startTimestamp to the seed. Otherwise we would generate the same data every hour.
@@ -134,7 +134,7 @@ private long getGeneratorStartTimestamp(List<DiagnosisKey> diagnosisKeys) {
       return getRetentionStartTimestamp();
     } else {
       DiagnosisKey latestDiagnosisKey = diagnosisKeys.get(diagnosisKeys.size() - 1);
-      return latestDiagnosisKey.getSubmissionTimestamp();
+      return latestDiagnosisKey.getSubmissionTimestamp() + 1;
     }
   }
 
diff --git a/services/distribution/src/test/java/app/coronawarn/server/services/distribution/objectstore/integration/ObjectStoreFilePreservationIT.java b/services/distribution/src/test/java/app/coronawarn/server/services/distribution/objectstore/integration/ObjectStoreFilePreservationIT.java
index e119a66e46..28a0cce2c5 100644
--- a/services/distribution/src/test/java/app/coronawarn/server/services/distribution/objectstore/integration/ObjectStoreFilePreservationIT.java
+++ b/services/distribution/src/test/java/app/coronawarn/server/services/distribution/objectstore/integration/ObjectStoreFilePreservationIT.java
@@ -132,7 +132,7 @@ void files_once_published_to_objectstore_should_not_be_overriden_because_of_rete
 
     triggerRetentionPolicy(testStartDate);
 
-    // Trigger second distrubution after data retention policies were applied
+    // Trigger second distribution after data retention policies were applied
     assembleAndDistribute(testOutputFolder.newFolder("output-after-retention"));
     List<S3Object> filesAfterRetention = getPublishedFiles();
 
diff --git a/services/distribution/src/test/java/app/coronawarn/server/services/distribution/runner/TestDataGenerationTest.java b/services/distribution/src/test/java/app/coronawarn/server/services/distribution/runner/TestDataGenerationTest.java
index c8eb644d31..422c636071 100644
--- a/services/distribution/src/test/java/app/coronawarn/server/services/distribution/runner/TestDataGenerationTest.java
+++ b/services/distribution/src/test/java/app/coronawarn/server/services/distribution/runner/TestDataGenerationTest.java
@@ -25,7 +25,9 @@
 import app.coronawarn.server.services.distribution.assembly.structure.util.TimeUtils;
 import app.coronawarn.server.services.distribution.config.DistributionServiceConfig;
 import app.coronawarn.server.services.distribution.config.DistributionServiceConfig.TestData;
+import org.junit.After;
 import org.junit.Assert;
+import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
@@ -76,6 +78,11 @@ void setup() {
     distributionServiceConfig.setTestData(testData);
   }
 
+  @AfterEach
+  void tearDown() {
+    TimeUtils.setNow(null);
+  }
+
   @Test
   void shouldCreateKeysAllKeys() {
     var now = LocalDateTime.of(2020, 7, 15, 12, 0, 0).toInstant(ZoneOffset.UTC);