diff --git a/beacon_node/execution_layer/src/test_utils/handle_rpc.rs b/beacon_node/execution_layer/src/test_utils/handle_rpc.rs
index d2c16da799..b9d9d76186 100644
--- a/beacon_node/execution_layer/src/test_utils/handle_rpc.rs
+++ b/beacon_node/execution_layer/src/test_utils/handle_rpc.rs
@@ -111,6 +111,9 @@ pub async fn handle_rpc<E: EthSpec>(
                             .map(|jep| JsonExecutionPayload::V1(jep))
                     })
                     .map_err(|s| (s, BAD_PARAMS_ERROR_CODE))?,
+                // From v3 onwards, we use the newPayload version only for the corresponding
+                // ExecutionPayload version. So we return an error instead of falling back to
+                // older versions of newPayload
                 ENGINE_NEW_PAYLOAD_V3 => get_param::<JsonExecutionPayloadV3<E>>(params, 0)
                     .map(|jep| JsonExecutionPayload::V3(jep))
                     .map_err(|s| (s, BAD_PARAMS_ERROR_CODE))?,
@@ -337,6 +340,9 @@ pub async fn handle_rpc<E: EthSpec>(
                     }
                     _ => unreachable!(),
                 }),
+                // From v3 onwards, we use the getPayload version only for the corresponding
+                // ExecutionPayload version. So we return an error if the ExecutionPayload version
+                // we get does not correspond to the getPayload version.
                 ENGINE_GET_PAYLOAD_V3 => Ok(match JsonExecutionPayload::from(response) {
                     JsonExecutionPayload::V3(execution_payload) => {
                         serde_json::to_value(JsonGetPayloadResponseV3 {