If you operate the unit manually, without the app, and set a separate timer on your phone or some such, it works fine. It's quiet and, so far, has been reliable for me. Even if the timer worked reliably, it doesn't actually do anything, except beep (forever). So, not having the timer is no great loss.
It's much like an old-fashioned kitchen oven: turn it on, wait until it's up to temperature, put in your cake or roast or whatever, and set a kitchen timer so you know when things are done.
That's not so hard, is it?
The not so much annoying, but embarrassing part of this story is how, whoever writes software for the Anova, has managed to repeatedly botch the timer function over many months and over many releases.
Just forget about the timer and the app. Set the temperature on the device, use a kitchen timer, and move on. Your life will less complicated, have one fewer annoyance, and your blood pressure will thank you for it.