Automation not triggered when scene is activated by another automation

Having this scene (S1) to turn off things when my son wakes up at 7am. So I have a time based automation (A1) to acitvate S1 at 7am. I also want the camera to be switch off 1hr later when he is still playing by himself in bed. But I would like this to be kinda part of the scene activation, so I have another automation (A2) listening the turn_on service event of S1 to turn off camera 1hr later, which is done according to this post.

So far so good, when I go to scenes menu to manually activate the scene, the A2 is triggered properly. But when A1 activates the S1, A2 is never triggered. Or when I click on the scene pill button on the dashboard, A2 is not triggered either.

Anyone knows the reason? Thanks in advance