By any chance have you used the cheat to max out anyone or everyone.I am not sure this has been discussed before but I did discover that if you add up plus 5 score and end up with a final result as 495 for excample and the game is programmed for this particular time to have 500 max you will nto get additional 5 score if u complete a scene. So you have to substract the 5 and then repeat the scene to get the plus 10 score. Not sure if this affects showing up or not of scenes but it might since the code does look into that. THis instance was with Rachel.
Also my cheat code stopped working so I can now only substract and never add....