I've checked the scene again. It's a bug. I will correct it with the next update, but it will be complicated.Still can't get Aly's teen photos. I can do the sunbed event with her, but cannot figure out how to trigger her sending me the photos.
Not to fix the code (already did that), but to fix the save game in case you've already done the scene the first time.
In order to fix it yourself, open the console and type:
player.inc_quest_state("Aly_breast_development",aly)
If the return falue is FALSE, you didn't see the initial event yet. Leave it alone for the moment and don't type the second command. If the return value is TRUE, type:
aly.add_queued_sexting(500,501,1)
close the console.
This should allow you to continue the quest.