Don't set the default document label in the view, do it at the task level which is accesible always.

mayan/apps/sources/tasks.py

@@ -38,6 +38,9 @@ def task_source_upload_document(label, document_type_id, shared_uploaded_file_id
     else:
         user = None
 
+    if not label:
+        label = shared_uploaded_file.filename
+
     with shared_uploaded_file.open() as file_object:
         source.upload_document(description=description, document_type=document_type, expand=expand, file_object=file_object, label=label, language=language, metadata_dict_list=metadata_dict_list, user=user)
 

mayan/apps/sources/views.py

@@ -215,10 +215,11 @@ class UploadInteractiveView(UploadBaseView):
 
         shared_uploaded_file = SharedUploadedFile.objects.create(file=uploaded_file.file)
 
-        label = shared_uploaded_file.filename
         if 'document_type_available_filenames' in forms['document_form'].cleaned_data:
             if forms['document_form'].cleaned_data['document_type_available_filenames']:
                 label = forms['document_form'].cleaned_data['document_type_available_filenames'].filename
+        else:
+            label = None
 
         if not self.request.user.is_anonymous():
             user_id = self.request.user.pk