Why didn't a verification code appear on one iPhone but appeared on other devices?

I have 3 iPads and 2 iPhones. I was on a banking app and the sent me a verification # to confirm my identity to change a setting. The # immediately appeared on my iPad but did not come on my iPhone. It did appear on my wife’s iPhone but ont the other 2 iPads. I don’t think that’s ever happened before.

[Re-Titled by Moderator]