diff --git a/src/backend/app/config.py b/src/backend/app/config.py
index f4c895cb6c..fc941b7fdf 100644
--- a/src/backend/app/config.py
+++ b/src/backend/app/config.py
@@ -174,7 +174,7 @@ def assemble_cors_origins(
 
         # Handle localhost/testing scenario
         domain = info.data.get("FMTM_DOMAIN", "fmtm.localhost")
-        dev_port = info.data.get("FMTM_DEV_PORT", "")
+        dev_port = info.data.get("FMTM_DEV_PORT")
         # NOTE fmtm.dev.test is used as the Playwright test domain
         if "localhost" in domain or "fmtm.dev.test" in domain:
             local_server_port = (
@@ -268,6 +268,7 @@ def configure_s3_download_root(cls, v: Optional[str], info: ValidationInfo) -> s
         else:
             fmtm_domain = info.data.get("FMTM_DOMAIN")
             # Local dev
+            # NOTE for automated tests, this is overridden manually
             if info.data.get("DEBUG"):
                 dev_port = info.data.get("FMTM_DEV_PORT")
                 return f"http://s3.{fmtm_domain}:{dev_port}"
diff --git a/src/backend/tests/conftest.py b/src/backend/tests/conftest.py
index 391fa1affb..71866da535 100644
--- a/src/backend/tests/conftest.py
+++ b/src/backend/tests/conftest.py
@@ -1,4 +1,4 @@
-# Copyright (c) 2022, 2023 Humanitarian OpenStreetMap Team
+# Copyright (c) Humanitarian OpenStreetMap Team
 #
 # This file is part of FMTM.
 #
@@ -23,6 +23,7 @@
 from io import BytesIO
 from pathlib import Path
 from typing import Any, AsyncGenerator
+from urllib.parse import urlparse
 from uuid import uuid4
 
 import pytest
@@ -248,11 +249,8 @@ async def odk_project(db, client, project, tasks):
         data_extracts,
     )
 
-    internal_file_path = (
-        f"{settings.S3_ENDPOINT}"
-        f"{data_extract_s3_path.split(settings.FMTM_DEV_PORT)[1]}"
-    )
-    response = requests.head(internal_file_path, allow_redirects=True)
+    internal_s3_url = f"{settings.S3_ENDPOINT}{urlparse(data_extract_s3_path).path}"
+    response = requests.head(internal_s3_url, allow_redirects=True)
     assert response.status_code < 400
 
     xlsform_file = Path(f"{test_data_path}/buildings.xls")
diff --git a/src/backend/tests/test_projects_routes.py b/src/backend/tests/test_projects_routes.py
index 9c836477ce..f53a8c26ea 100644
--- a/src/backend/tests/test_projects_routes.py
+++ b/src/backend/tests/test_projects_routes.py
@@ -1,4 +1,4 @@
-# Copyright (c) 2022, 2023 Humanitarian OpenStreetMap Team
+# Copyright (c) Humanitarian OpenStreetMap Team
 #
 # This file is part of FMTM.
 #
@@ -22,6 +22,7 @@
 from io import BytesIO
 from pathlib import Path
 from unittest.mock import Mock, patch
+from urllib.parse import urlparse
 from uuid import uuid4
 
 import pytest
@@ -359,12 +360,8 @@ async def test_generate_project_files(db, client, project):
         data_extracts,
     )
     assert data_extract_s3_path is not None
-    # Test url, but first sub localhost url with docker network for backend connection
-    internal_file_path = (
-        f"{settings.S3_ENDPOINT}"
-        f"{data_extract_s3_path.split(settings.FMTM_DEV_PORT)[1]}"
-    )
-    response = requests.head(internal_file_path, allow_redirects=True)
+    internal_s3_url = f"{settings.S3_ENDPOINT}{urlparse(data_extract_s3_path).path}"
+    response = requests.head(internal_s3_url, allow_redirects=True)
     assert response.status_code < 400
 
     # Get custom XLSForm path