diff --git a/data/beaconrestapi/src/integration-test/java/tech/pegasys/teku/beaconrestapi/v1/beacon/PostAttesterSlashingIntegrationTest.java b/data/beaconrestapi/src/integration-test/java/tech/pegasys/teku/beaconrestapi/v1/beacon/PostAttesterSlashingIntegrationTest.java
index 92d670a017d..142d14ee5b4 100644
--- a/data/beaconrestapi/src/integration-test/java/tech/pegasys/teku/beaconrestapi/v1/beacon/PostAttesterSlashingIntegrationTest.java
+++ b/data/beaconrestapi/src/integration-test/java/tech/pegasys/teku/beaconrestapi/v1/beacon/PostAttesterSlashingIntegrationTest.java
@@ -62,9 +62,7 @@ public void shouldReturnServerErrorWhenUnexpectedErrorHappens() throws Exception
     final Response response =
         post(
             PostAttesterSlashing.ROUTE,
-            JsonUtil.serialize(
-                slashing,
-                slashing.getSchema().castTypeToAttesterSlashingSchema().getJsonTypeDefinition()));
+            JsonUtil.serialize(slashing, slashing.getSchema().getJsonTypeDefinition()));
     assertThat(response.code()).isEqualTo(SC_INTERNAL_SERVER_ERROR);
   }
 
@@ -78,9 +76,7 @@ public void shouldReturnSuccessWhenRequestBodyIsValid() throws Exception {
     final Response response =
         post(
             PostAttesterSlashing.ROUTE,
-            JsonUtil.serialize(
-                slashing,
-                slashing.getSchema().castTypeToAttesterSlashingSchema().getJsonTypeDefinition()));
+            JsonUtil.serialize(slashing, slashing.getSchema().getJsonTypeDefinition()));
 
     verify(attesterSlashingPool).addLocal(slashing);
 
diff --git a/data/beaconrestapi/src/integration-test/java/tech/pegasys/teku/beaconrestapi/v2/beacon/PostAttesterSlashingV2IntegrationTest.java b/data/beaconrestapi/src/integration-test/java/tech/pegasys/teku/beaconrestapi/v2/beacon/PostAttesterSlashingV2IntegrationTest.java
index a9905fbaec2..ec8a79a9c54 100644
--- a/data/beaconrestapi/src/integration-test/java/tech/pegasys/teku/beaconrestapi/v2/beacon/PostAttesterSlashingV2IntegrationTest.java
+++ b/data/beaconrestapi/src/integration-test/java/tech/pegasys/teku/beaconrestapi/v2/beacon/PostAttesterSlashingV2IntegrationTest.java
@@ -81,9 +81,7 @@ public void shouldReturnServerErrorWhenUnexpectedErrorHappens() throws Exception
     final Response response =
         post(
             PostAttesterSlashingV2.ROUTE,
-            JsonUtil.serialize(
-                slashing,
-                slashing.getSchema().castTypeToAttesterSlashingSchema().getJsonTypeDefinition()),
+            JsonUtil.serialize(slashing, slashing.getSchema().getJsonTypeDefinition()),
             Collections.emptyMap(),
             Optional.of(specMilestone.name().toLowerCase(Locale.ROOT)));
     assertThat(response.code()).isEqualTo(500);
@@ -99,9 +97,7 @@ public void shouldReturnSuccessWhenRequestBodyIsValid() throws Exception {
     final Response response =
         post(
             PostAttesterSlashingV2.ROUTE,
-            JsonUtil.serialize(
-                slashing,
-                slashing.getSchema().castTypeToAttesterSlashingSchema().getJsonTypeDefinition()),
+            JsonUtil.serialize(slashing, slashing.getSchema().getJsonTypeDefinition()),
             Collections.emptyMap(),
             Optional.of(specMilestone.name().toLowerCase(Locale.ROOT)));
 
@@ -117,9 +113,7 @@ void shouldFailWhenMissingConsensusHeader() throws Exception {
     final Response response =
         post(
             PostAttesterSlashingV2.ROUTE,
-            JsonUtil.serialize(
-                slashing,
-                slashing.getSchema().castTypeToAttesterSlashingSchema().getJsonTypeDefinition()));
+            JsonUtil.serialize(slashing, slashing.getSchema().getJsonTypeDefinition()));
 
     assertThat(response.code()).isEqualTo(SC_BAD_REQUEST);
 
@@ -139,9 +133,7 @@ void shouldFailWhenBadConsensusHeaderValue() throws Exception {
     final Response response =
         post(
             PostAttesterSlashingV2.ROUTE,
-            JsonUtil.serialize(
-                slashing,
-                slashing.getSchema().castTypeToAttesterSlashingSchema().getJsonTypeDefinition()),
+            JsonUtil.serialize(slashing, slashing.getSchema().getJsonTypeDefinition()),
             Collections.emptyMap(),
             Optional.of(badConsensusHeaderValue));