Heathric, I haven't installed this yet. but the same issue happened to me and I am running .592 on my 8900.
My wife sent me an mp3 that was like 90kb, was a funny ringtone. All I did was play it. Never saved it. And everytime after a call, the message would play. I eventually downloaded the ringtone and deleted the MMS message then it stopped. I sent it to a friend as MMS, never saw the problem again, but was weird. Never tried rebooting (my phone is a business number), I try to leave rebooting until late night