Face-to-face (plugin)

I have set two different face-to-face activities in the same course. Both are set not to require approval.
While I (the manager) receive a message every time a student signs-up for a session of the first activity, I don't receive any message when they sign for the second one.
I am trying a workaround duplicating my email address in the "third-party notification" field (I just did it, let's see whether it works), but I wonder wether there is something that I did wrong

This is with moodle 2.6

thanks,
Piersante