Hmm. Just tested the timer notification and it didn't work (set a 5 minute timer on my existing cook).
Version of the app is 2.7.0.
I'm actually running the iOS beta - 11.3 - public beta 2 (bundle 15E5178f)
I'll try testing a couple of the other notifications.
Oho! I'm not signed into the Anova cloud....see if that's it.
Also turned off my wifi and bluetooth on my phone - should be able to get the notification over cellular.