iPhone Alarm Goes Off During Phone Call, Locks Up Screen/Phone

I have an iPhone 7S Plus (running iOS 11.2.5 [15D60]).

This has happened on not only this newest 7S Plus of mine, but also my previous 7S Plus.

I'll be in the middle of a phone call and an alarm will go off.

Now, there are two options:

1. If I hit the Home button, then disable/snooze the alarm from there, there is no problem.
2. However, sometimes when I Snooze the alarm from the dropdown/pop-up screen, or press the down volume button, the alarm snoozes (and will go off again in 9 minutes), but an odd thing happens...all of the my phone's keypad goes away, and I'm left looking at my Homescreen background picture (with no icons whatsoever), or my LockScreen photo, and I can't get out of either. Also, I now no longer have the option to "Stop" the alarm when it goes off again, so I have to "Down Volume/Snooze" the alarm when it goes off every 9 minutes during the phone call, until the phone call ends. Needless to say, snoozing an alarm every 9 minutes (because you no longer have the option to turn it off, only Snooze it), during a long phone call, is very annoying. Even after the phone call has ended, I'm left looking at my HomeScreen (or LockScreen) background picture, with no buttons/icons to press, and regardless of what I press after that (volume buttons, Home button, Sleep/Wake button), I cannot get ANYWHERE on the phone. The ONLY thing that I'm allowed to do is if I hit the Home button twice in quick succession, Apple Pay will come up. Other than that, if an alarm goes off during a phone call and I disable/snooze an alarm the wrong way, I have to restart my phone after the call is over, because it won't let me do ANYTHING (other than that).

Any suggestions?