Sometimes if I click Monzo notification it causes my phone to restart.
Odd that an app causes this, which doesn’t seem possible, but just posting to see if I’m the only one?
Google Pixel 6 Pro, Android 12 SQ3A.220705.003
Monzo Version 4.40.1
If I click the notification then authenticate with my fingerprint, my whole phone crashes and restarts.
Have you tried deleting and reinstalling the app?
Not quite the same I know but on iOS for the last three or so weeks,if I happen to restart my phone the Monzo app fails to start. I then have to delete and reinstall the app which cures the problem until I reboot my phone again.
Didn’t have the issue previously and only the Monzo app is affected. 
An app couldn’t cause the whole phone to crash… it sounds faulty TBH as a bug in android 12 capable of it would well known by now.