Okay, I had this specific (I think) problem. Basically I have finished EP4 but the game when I go into says I still haven't finished the very last section of it (even though I have, and even sat through the whole credits, and have the achievements to prove it). I played through the end again two times. Each time after it drops back to the main menu it correctly says that I had now completed EP4, however it also now said that EP5 was "coming soon". Restarting the game opens up EP5, but EP4's status goes back to unfinished/the very last savepoint before the end. When you go into your save files however it looks like every decision was still saved for me, including the ones at the end of EP4 (show the bite, who do you take with you, what you say to the stranger).
Basically if you just start EP5 and let it "auto gen" the choices it will go with the choices you made anyway... as long as you actually played through the end of EP4 and the choices were saved. It's pretty easy to check anyway just start EP5 and watch the "previously on..." and it should be the same choices you made in EP4, even though you picked "auto gen choices".