Ah… I think this may be the reason … as explained here by Product Manager Ben…
You will get hourly (not instant) alerts on from your app, but need to have permissions set to ON for your mobile device. Have you seen alerts come through from the app? I tend to use the app for notifications when I have searches set, and revert to the website when making applications (I’m not a fast or accurate phone typist!!).
Let me also tag @Lucy-B here as she may have some further insight or advice to offer on best practices for this topic.