I never liked content hidden in transitions. Feels like a cheap way to waste people's time under the guise of making people more engaged in the story.
Transitions are just Renpy's word for making animations from image frames and effects inside the game engine rather than simply playing a video file that has all the shown content. Also, advancing during a transition simply skips the timed pause/effect (just like you advance dialogue using Enter, Space or LMB) rather than ending the whole video file.
Transitions are by default showed even though the preference setting indicates that they are skipped. If the "Transitions" text in settings is dark, transitions ARE BEING skipped in all AE versions up to 2.2.1. It will be fixed in the next update.