Hopefully this helps some, and especially the devs...
After downloading episode 4, the only save file that would load up is episode two. Trying to load slot one, would end up loading slot 2. Any matter of copying your other save files into slot two would end up choosing random choices for you. Obviously this is unacceptable.
I ended up uninstalling the Episode 4 DLC. Interestingly enough, all my save files could load up okay and with the correct decisions. Since this bug appeared to only allow me to open up slot 2, I decided to copy my normal game into slot 2 if the bug should arise again. After this: Redownload episode 4 (not that I think it makes a difference but I did it from in TWD.)
Upon loading up the saves, They are still buggy, I can't load slot three, upon loading slot three, it loads up the other slot.
Anyway, At least I can play from my normal save file now, If this works for anyone else please post here to let us all know.
Hopefully this works for ya'll Believe me I know how frustrating this is.
Upon further data gathering, it now appears that the game is stuck on loading slot one. This is the normal save file I want to play from anyway, but at least I can play. As I say, Try this with the slot you want to play as and we can narrow down if this is a decent work around or a fluke.