How often did this happen? This is the first time this has been reported.
Normally when the LL line has a lot of guests in it, CMs will load more LL guests to the attraction than standby guests.
We'll see if others share the same experience but I would wait to see what others report. Are you still there now? If so, I would find a guest entering the standby line at the same time you're entering the LL and then see when each of you boards the ride.