diff --git a/src/steps/da.py b/src/steps/da.py
index 67af39d..32bda30 100644
--- a/src/steps/da.py
+++ b/src/steps/da.py
@@ -1,5 +1,4 @@
 import allure
-from requests.packages import target
 from tenacity import retry, stop_after_delay, wait_fixed
 
 from src.env_vars import NOMOS_EXECUTOR
@@ -46,7 +45,7 @@ class StepsDataAvailability(StepsCommon):
         return executor
 
     @allure.step
-    def disperse_data(self, data, app_id, index, client_node=None, timeout_duration=65, utf8=True, padding=True):
+    def disperse_data(self, data, app_id, index, client_node=None, timeout_duration=65, utf8=True, padding=True, send_invalid=False):
         @retry(stop=stop_after_delay(timeout_duration), wait=wait_fixed(0.1), reraise=True)
         def disperse(my_self=self):
             response = []
@@ -57,7 +56,10 @@ class StepsDataAvailability(StepsCommon):
                 if client_node is None:
                     response = executor.send_dispersal_request(request)
                 else:
-                    client_node.set_rest_api(executor.name(), executor.api_port_internal())
+                    if send_invalid:
+                        client_node.set_invalid_rest_api(executor.name(), executor.api_port_internal())
+                    else:
+                        client_node.set_rest_api(executor.name(), executor.api_port_internal())
                     response = client_node.send_dispersal_request(request)
             except Exception as ex:
                 assert "Bad Request" in str(ex) or "Internal Server Error" in str(ex)
@@ -70,7 +72,7 @@ class StepsDataAvailability(StepsCommon):
         return disperse()
 
     @allure.step
-    def get_data_range(self, node, app_id, start, end, client_node=None, timeout_duration=45):
+    def get_data_range(self, node, app_id, start, end, client_node=None, timeout_duration=45, send_invalid=False):
         @retry(stop=stop_after_delay(timeout_duration), wait=wait_fixed(0.1), reraise=True)
         def get_range():
             response = []
@@ -79,7 +81,10 @@ class StepsDataAvailability(StepsCommon):
                 if client_node is None:
                     response = node.send_get_data_range_request(query)
                 else:
-                    client_node.set_rest_api(node.name(), node.api_port_internal())
+                    if send_invalid:
+                        client_node.set_invalid_rest_api(node.name(), node.api_port_internal())
+                    else:
+                        client_node.set_rest_api(node.name(), node.api_port_internal())
                     response = client_node.send_get_data_range_request(query)
             except Exception as ex:
                 assert "Bad Request" in str(ex) or "Internal Server Error" in str(ex)
diff --git a/tests/dos_robustness/test_high_load_dos.py b/tests/dos_robustness/test_high_load_dos.py
index adc2076..a30ea5e 100644
--- a/tests/dos_robustness/test_high_load_dos.py
+++ b/tests/dos_robustness/test_high_load_dos.py
@@ -155,3 +155,55 @@ class TestHighLoadDos(StepsDataAvailability):
 
         assert failure_ratio_w < 0.20, f"Dispersal failure ratio {failure_ratio_w} too high"
         assert failure_ratio_r < 0.20, f"Data download failure ratio {failure_ratio_r} too high"
+
+    @pytest.mark.usefixtures("setup_2_node_cluster", "setup_client_nodes")
+    def test_sustained_high_rate_with_invalid_requests(self):
+        timeout = 10
+        start_time = time.time()
+        successful_dispersals = 0
+        unsuccessful_dispersals = 0
+        successful_downloads = 0
+        unsuccessful_downloads = 0
+
+        while True:
+            if time.time() - start_time > timeout:
+                break
+
+            dispersal_cl, download_cl = random.choice(self.client_nodes), random.choice(self.client_nodes)
+
+            delay(0.01)
+            invalid = random.choice([True, False])
+
+            try:
+                response = self.disperse_data(
+                    DATA_TO_DISPERSE[6], to_app_id(1), to_index(0), client_node=dispersal_cl, timeout_duration=0, send_invalid=invalid
+                )
+                if response.status_code == 200:
+                    successful_dispersals += 1
+                elif not invalid:
+                    unsuccessful_dispersals += 1
+            except Exception:
+                if not invalid:
+                    unsuccessful_dispersals += 1
+
+            try:
+                invalid = random.choice([True, False])
+                self.get_data_range(
+                    self.node2, to_app_id(1), to_index(0), to_index(5), client_node=download_cl, timeout_duration=0, send_invalid=invalid
+                )
+                successful_downloads += 1
+            except Exception:
+                if not invalid:
+                    unsuccessful_downloads += 1
+
+        assert successful_dispersals > 0, "No successful dispersals"
+        assert successful_downloads > 0, "No successful downloads"
+
+        failure_ratio_w = unsuccessful_dispersals / successful_dispersals
+        failure_ratio_r = unsuccessful_downloads / successful_downloads
+
+        logger.info(f"Unsuccessful dispersals ratio: {failure_ratio_w}")
+        logger.info(f"Unsuccessful download ratio: {failure_ratio_r}")
+
+        assert failure_ratio_w < 0.20, f"Dispersal failure ratio {failure_ratio_w} too high"
+        assert failure_ratio_r < 0.20, f"Data download failure ratio {failure_ratio_r} too high"