Rename the custom middleware to ensure it's know this is a localemiddleware. Also ensure we delete the Vary header, it could be empty - still problematic

config.py

@@ -31,7 +31,7 @@ INSTALLED_APPS.extend(
 
 MIDDLEWARE.extend(
     [
-        "ivatar.middleware.RemoveVaryForImagesMiddleware",
+        "ivatar.middleware.CustomLocaleMiddleware",
     ]
 )
 MIDDLEWARE.insert(

ivatar/middleware.py

@@ -7,7 +7,7 @@ from django.utils.deprecation import MiddlewareMixin
 from django.middleware.locale import LocaleMiddleware
 
 
-class RemoveVaryForImagesMiddleware(LocaleMiddleware):
+class CustomLocaleMiddleware(LocaleMiddleware):
     """
     Middleware that extends LocaleMiddleware to skip Vary header processing for image URLs
     """
@@ -19,6 +19,11 @@ class RemoveVaryForImagesMiddleware(LocaleMiddleware):
             path.startswith(prefix)
             for prefix in ["/avatar/", "/gravatarproxy/", "/blueskyproxy/"]
         ):
+            # Debug print
+            print(f"DEBUG: Processing image URL: {path}")
+            # Delete Vary from header if exists
+            if "Vary" in response:
+                del response["Vary"]
             # Skip the parent's process_response to avoid adding Accept-Language to Vary
             return response