diff --git a/apps/SeleniumService/selenium_UnitedDH_claimSubmitWorker.py b/apps/SeleniumService/selenium_UnitedDH_claimSubmitWorker.py
index 21d4125f..c69d23d0 100644
--- a/apps/SeleniumService/selenium_UnitedDH_claimSubmitWorker.py
+++ b/apps/SeleniumService/selenium_UnitedDH_claimSubmitWorker.py
@@ -1096,11 +1096,16 @@ class AutomationUnitedDHClaimSubmit:
                 print(f"[UnitedDH Claim] step7: Could not click caret (section may already be open): {e}")
 
             attached = 0
+            seen_paths = set()
             for cf in self.claimFiles:
                 relative_path = cf.get("filePath") or ""
                 if not relative_path:
                     print(f"[UnitedDH Claim] step7: Skipping file with no filePath: {cf}")
                     continue
+                if relative_path in seen_paths:
+                    print(f"[UnitedDH Claim] step7: Skipping duplicate file: {relative_path}")
+                    continue
+                seen_paths.add(relative_path)
 
                 abs_path = os.path.normpath(os.path.join(_BACKEND_CWD, relative_path.lstrip("/")))
                 if not os.path.isfile(abs_path):
@@ -1113,6 +1118,10 @@ class AutomationUnitedDHClaimSubmit:
                         EC.presence_of_element_located((By.XPATH, "//input[@type='file']"))
                     )
                     self.driver.execute_script("arguments[0].removeAttribute('class');", file_input)
+                    # The input is a multi-file input and chromedriver APPENDS on send_keys,
+                    # so a leftover selection from the previous iteration re-uploads the
+                    # earlier file (2 attachments became 3). Clear it first.
+                    self.driver.execute_script("arguments[0].value = '';", file_input)
                     file_input.send_keys(abs_path)
                     WebDriverWait(self.driver, 60).until(
                         EC.element_to_be_clickable((By.XPATH,
diff --git a/apps/SeleniumService/selenium_UnitedDH_preAuthWorker.py b/apps/SeleniumService/selenium_UnitedDH_preAuthWorker.py
index 5eb2092c..76e40f73 100644
--- a/apps/SeleniumService/selenium_UnitedDH_preAuthWorker.py
+++ b/apps/SeleniumService/selenium_UnitedDH_preAuthWorker.py
@@ -1035,11 +1035,16 @@ class AutomationUnitedDHPreAuth:
                 print(f"[UnitedDH PreAuth] step7: Could not click caret (section may already be open): {e}")
 
             attached = 0
+            seen_paths = set()
             for cf in self.claimFiles:
                 relative_path = cf.get("filePath") or ""
                 if not relative_path:
                     print(f"[UnitedDH PreAuth] step7: Skipping file with no filePath: {cf}")
                     continue
+                if relative_path in seen_paths:
+                    print(f"[UnitedDH PreAuth] step7: Skipping duplicate file: {relative_path}")
+                    continue
+                seen_paths.add(relative_path)
 
                 abs_path = os.path.normpath(os.path.join(_BACKEND_CWD, relative_path.lstrip("/")))
                 if not os.path.isfile(abs_path):
@@ -1052,6 +1057,10 @@ class AutomationUnitedDHPreAuth:
                         EC.presence_of_element_located((By.XPATH, "//input[@type='file']"))
                     )
                     self.driver.execute_script("arguments[0].removeAttribute('class');", file_input)
+                    # The input is a multi-file input and chromedriver APPENDS on send_keys,
+                    # so a leftover selection from the previous iteration re-uploads the
+                    # earlier file (2 attachments became 3). Clear it first.
+                    self.driver.execute_script("arguments[0].value = '';", file_input)
                     file_input.send_keys(abs_path)
                     WebDriverWait(self.driver, 60).until(
                         EC.element_to_be_clickable((By.XPATH,