[Bug] Very weird bug won't let me start Episode 5

[Robil]

I have a really weird problem playing Episode 5...

When I click to play Episode 5, the game tells me that I don't have a save that has completed Episode 4, so it will have to fill in some decisions for me. If I go back and play the last few minutes of Episode 4, or even just load up Episode 4 and then immediately quit out, then it switches to saying that Episode 5 is 'Coming Soon' and I can't select it at all, as if it wasn't even out yet!

I've tried uninstalling and reinstalling, verifying integrity, etc - doesn't seem to make a difference. At first I thought I was running into one of the dreaded save bugs, but the whole 'Coming Soon' thing really makes me think it's something else... I really don't know why the game would revert to thinking it doesn't have Episode 5 every time I play the end of Episode 4....

Has anyone else had this bug? Any suggestions?