diff --git a/core/src/main/java/io/kestra/core/serializers/JacksonMapper.java b/core/src/main/java/io/kestra/core/serializers/JacksonMapper.java
index abcb9528f78..cc9db385b7f 100644
--- a/core/src/main/java/io/kestra/core/serializers/JacksonMapper.java
+++ b/core/src/main/java/io/kestra/core/serializers/JacksonMapper.java
@@ -121,6 +121,7 @@ public static ObjectMapper ofIon() {
     private static ObjectMapper configure(ObjectMapper mapper) {
         return mapper
             .configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false)
+            .configure(SerializationFeature.WRITE_DURATIONS_AS_TIMESTAMPS, false)
             .setSerializationInclusion(JsonInclude.Include.NON_NULL)
             .registerModule(new JavaTimeModule())
             .registerModule(new Jdk8Module())
diff --git a/core/src/test/java/io/kestra/core/repositories/AbstractExecutionRepositoryTest.java b/core/src/test/java/io/kestra/core/repositories/AbstractExecutionRepositoryTest.java
index 1fbfba06c89..b8a36424b81 100644
--- a/core/src/test/java/io/kestra/core/repositories/AbstractExecutionRepositoryTest.java
+++ b/core/src/test/java/io/kestra/core/repositories/AbstractExecutionRepositoryTest.java
@@ -95,9 +95,9 @@ static State randomDuration(State.Type state) {
         );
 
         Random rand = new Random();
-        doReturn(Duration.ofSeconds(rand.nextInt(150)))
+        doReturn(Instant.now().plusMillis(rand.nextInt(150)))
             .when(finalState)
-            .getDuration();
+            .getStartDate();
 
         return finalState;
     }
@@ -287,14 +287,11 @@ protected void dailyGroupByFlowStatistics() throws InterruptedException {
         DailyExecutionStatistics full = result.get("io.kestra.unittest").get(FLOW).get(10);
         DailyExecutionStatistics second = result.get("io.kestra.unittest").get("second").get(10);
 
-        assertThat(full.getDuration().getAvg().toMillis(), greaterThan(0L));
         assertThat(full.getExecutionCounts().size(), is(11));
         assertThat(full.getExecutionCounts().get(State.Type.FAILED), is(3L));
         assertThat(full.getExecutionCounts().get(State.Type.RUNNING), is(5L));
         assertThat(full.getExecutionCounts().get(State.Type.SUCCESS), is(7L));
         assertThat(full.getExecutionCounts().get(State.Type.CREATED), is(0L));
-
-        assertThat(second.getDuration().getAvg().toMillis(), greaterThan(0L));
         assertThat(second.getExecutionCounts().size(), is(11));
         assertThat(second.getExecutionCounts().get(State.Type.SUCCESS), is(13L));
         assertThat(second.getExecutionCounts().get(State.Type.CREATED), is(0L));
@@ -313,7 +310,6 @@ protected void dailyGroupByFlowStatistics() throws InterruptedException {
         assertThat(result.size(), is(1));
         assertThat(result.get("io.kestra.unittest").size(), is(1));
         full = result.get("io.kestra.unittest").get("*").get(10);
-        assertThat(full.getDuration().getAvg().toMillis(), greaterThan(0L));
         assertThat(full.getExecutionCounts().size(), is(11));
         assertThat(full.getExecutionCounts().get(State.Type.FAILED), is(3L));
         assertThat(full.getExecutionCounts().get(State.Type.RUNNING), is(5L));
@@ -440,8 +436,6 @@ protected void dailyStatistics() throws InterruptedException {
 
         assertThat(result.size(), is(11));
         assertThat(result.get(10).getExecutionCounts().size(), is(11));
-        assertThat(result.get(10).getDuration().getAvg().toMillis(), greaterThan(0L));
-
         assertThat(result.get(10).getExecutionCounts().get(State.Type.FAILED), is(3L));
         assertThat(result.get(10).getExecutionCounts().get(State.Type.RUNNING), is(5L));
         assertThat(result.get(10).getExecutionCounts().get(State.Type.SUCCESS), is(21L));
diff --git a/core/src/test/java/io/kestra/plugin/core/kv/SetTest.java b/core/src/test/java/io/kestra/plugin/core/kv/SetTest.java
index 36e79846610..58abf00303b 100644
--- a/core/src/test/java/io/kestra/plugin/core/kv/SetTest.java
+++ b/core/src/test/java/io/kestra/plugin/core/kv/SetTest.java
@@ -209,8 +209,7 @@ void typeSpecified() throws Exception {
         assertThat(kv.getValue(TEST_KEY).get().value(), is(Instant.parse("2023-05-02T01:02:03Z")));
 
         set.toBuilder().value("P1DT5S").kvType(KVType.DURATION).build().run(runContext);
-        // TODO Hack meanwhile we handle duration serialization as currently they are stored as bigint...
-        assertThat((long) Double.parseDouble(kv.getValue(TEST_KEY).get().value().toString()), is(Duration.ofDays(1).plus(Duration.ofSeconds(5)).toSeconds()));
+        assertThat(kv.getValue(TEST_KEY).get().value(), is(Duration.ofDays(1).plus(Duration.ofSeconds(5))));
 
         set.toBuilder().value("[{\"some\":\"value\"},{\"another\":\"value\"}]").kvType(KVType.JSON).build().run(runContext);
         assertThat(kv.getValue(TEST_KEY).get().value(), is(List.of(Map.of("some", "value"), Map.of("another", "value"))));