For me, the frozen state looks just like the normal screen. It just that no new notifications show up and none of the keys/buttons register being pushed.
** edited to add a screenshot of my phone after not being on it for an hour (since the above message posted) and the app was frozen when I tried to go back in (It shows I posted on this thread 1 minute ago but it was actually an hour ago)
I have been unable to replicate this on my personal phone. However, I did find a few crash logs. It looks like it only affects a small group of people. I’ve applied a fix that should resolve it - but it’s hard to be certain if I can’t replicate it.
This will be in 4.0.55 which I will release in a few days.
I just released version 4.0.55. It’s on a staged roll out and will become steadily available for everyone over the course of a few days. Keep an eye on the store.