I'm playing on on the PlayStation version. I had a theory that because I have to run from the slog immediately after chanting, the portal is not fully formed when I cross to the previous screen, idk if that would cause it to malfunction but that's all I could come up with. Other than that I cant think of what to do, is there a way I can skip this level (after all I played through the whole thing minus this hiccup)?
And as for the slog not eating me, it seems that when he makes contact with me behind the portal it just doesn't attack. I can walk back to the previous screen and then he will eventually run after me and indeed kill me if it gets at me. Yet still attempting a second run at the already open portal results in me standing behind the portal once more and the slog not eating me. Its rather Odd