Fix auto assign author

api/v1/serializers/course.py

@@ -142,7 +142,7 @@ class CourseCreateSerializer(DispatchContentMixin,
         materials = validated_data.pop('materials', [])
         gallery = validated_data.pop('gallery', {})
         author = validated_data.get('author', None)
-        if not instance.author or not author:
+        if not instance.author or author and instance.author != author:
             validated_data['author'] = self.context['request'].user
         course = super().update(instance, validated_data)
         self.dispatch_materials(course, materials)