Huge fix.

taggit/views.py

@@ -11,7 +11,7 @@ def tagged_object_list(request, slug, queryset, **kwargs):
     tag = get_object_or_404(Tag, slug=slug)
     qs = queryset.filter(pk__in=TaggedItem.objects.filter(
         tag=tag, content_type=ContentType.objects.get_for_model(queryset.model)
-    ))
+    ).values_list("object_id", flat=True))
     if "extra_context" not in kwargs:
         kwargs["extra_context"] = {}
     kwargs["extra_context"]["tag"] = tag