The alley encounter is on Victorious after doing the debrief for the ship/bank heist. If you played the athletes scene in an old version before the CG was added, it's possible that the gallery flag was never set, I'll look into adding a check for that in my savegame compatibility code. Office replays don't set any flags. As for the XO, there aren't currently any scenes unlocking their nude gallery as they only get partially stripped in each of their current scenes, might change that.
Edit: There may be an issue with the flag being checked for both the alley scene and the local shop, I'll make some changes there.