Missing 9-2 Cutscene Workaround
Threw enough linkshell minions at this longstanding bug to find a work around.
The bug will affect (a) the first person to enter the battlefield (b) after first entering the area. Even if everyone leaves the battlefield and re-enters (without leaving the area entirely), that same person still will not get the CS.
In order to get the opening CS, you need (a) the "Battlefield" status icon (b) the first time you try entering the battlefield after entering the area.
Therefore, the work-around is to have everyone enter, then leave one person (at least) in the battlefield while anyone who missed the CS leaves the battlefield and the area entirely before trying to enter again.
Remember not to engage any enemies before then, or anybody outside will be denied entry.
Soloers are obviously out of luck and are stuck with having to come back to check the Goblin Footprints after officially completing the mission entirely (i.e. reaching rank 10)