Since 2 people have reported this, it appears to be a problem under some specific configuration (since most installations don't have the problem). So I will need to get more information to help try to debug it.
As I asked Nicolas, can you please make the following change in qa-config.php so I can see what database queries are being sent:
... to ...
Also, are you able to send me a dump of the database contents, especially the qa_posts table?