Dead Space 3: cannot open prologue from "chapter selection"

Hi, I'm facing a quite annoying problem here: after installing the game, I went directly to co-op mode, and joined someone by skipping the first part of Prologue ( I didn't choose it, probably it was because the other player was already playing, and I just needed to wait to join him at the next check point.. even for the first time... ), jumping directly into the second one where Tim has just got the codex and began to slide down from the mountain. 

I played for a while, until chapter 2 I think, and then chose "save and quit", as normally everybody does.  A few days later, when I realised that I skipped the SCAF artifact at the very beginning of Prologue, I chose the one save file that ever existed in my game, and wanted to play by choosing "chapter selection", except that I couldn't. It showed that I had played Prologue, the completion was 98%, and artifact collection in Prologue was 0/1. But when I hit the confirm button, nothing came up. However when I chose the other following chapters, the process always prevailed, there was no problem.

I think it is because I didn't play the first part of Prologue at all, so there is no coresponding save data to kick Prologue start whatsoever. With this bug existing, I can no longer get into the prologue with the related save file, since there seems to be one way that I can do it -- chapter selection. By now I've got 100% completion from chapter 2 to chapter 9, before I spot this problem. Could you fix it?

If not I suppose I would have to open up another save slot and preceed from the very start, again...