If I have the same item in 2 Cartwall slots and (using Extra PFL), I set the Cue Point on one of them (for example: a song hook), the other item also inherits the Cue settings and both buttons are then duplicated. This happens when you click “OK” on the PFL dialogue.
I swear that the you could set points individually for each item on the Cartwall and regardless of the same audio being present, the Cues would be individual ?!
EDIT: Also changes the main Playlist timings too 
So you dragged the item from the main playlist? This is a bug. The cart players should create a copy of the item instead of just keeping a reference.
Yes - I was just playing around, and noticed that the Cue Points in the CartWall fed back to the Playlist and also the 2nd copy of that audio track (if it was duplicated on the CartWall). So, for the purposes of creating a CartWall button set to play a song hook - you have to reset the song’s Cue Point as the Playlist copy will play from the same point ;(
Will be fixed in v.40.