Hi,
I guess this is problem with IMAP folder sync. I observed same issue while using Gmail on Nokia Messaging.
I have added my OVI mail account on Nokia Messaging. Now whenever I login to webmail, I see folder "Sent Items" , I guess this is from Nokia Messaging sent folder.
I am not sure whom to report this bug but as I reported this to Nokia messaging, same I am doing here with Mail on OVI.
Since both services are from Nokia, I think both teams can work together and resolve it soon.
Suyog