No notification sounds from Geary?

I’ve noticed that, despite having activated the notifications for all apps (actually they were on by default), I don’t get sounds when an email comes in. The blue LED lights up but no sounds.
I get sounds when an SMS arrives, even if the sound has nothing to do with the “Alert Sound” set.
A negligible problem, but I would like to know whether it’s just mine.

I just tested. Mine also doesn’t produce a sound, only the LED.