When I started Game 4 I found out that there were two guideposts looking exactly the same. I picked one at random. Was that ok?
I also checked that Game 4 is not the only game with two exact guidepost.
I usually select them from the index. Is there a special mechanism to choose the guidepost for the next game?
Do both cards have the same number?
If so, that's probably a packaging mistake.
If not, then I bet the lettered crate that you opened when processing the guidepost for game 3 (at the end of game 3) wasn't read closely enough.
That crate should Have directed you to fetch a story card and a new guidepost (and I think a new rule).