How do I report a bug with the mobile app?
Showing the pass at a ticket check seems to try & make a connection. If the phone is connected to on-train WiFi but the signal is (temporarily) poor then the app just stalls / hangs. This is a very uncomfortable experience when the train manager/guard/<whatever> is standing next to you.
The same applies if the phone is connected to 3G/4G and the signal is poor.
I had to turn off WiFi and/or turn off mobile data and then it’s fine. The app was fine once it knew there was no connection at all - it was just upset by a bad connection.
I worked this out but then I work with IT. Someone less aware of IT or who doesn’t know how to turn off WiFi and/or mobile data could have an uncomfortable experience.