Hi Rufus7437,
To try to stop this from happening again, you could try restarting your iPhone 12. A restart can refresh the iOS and apps on a device, which can sometimes resolve or stop issues from happening again. If needed, the steps below show how:
"How to restart your iPhone X, 11, 12, 13, or later
- Press and hold either volume button and the side button until the power-off slider appears.
- Drag the slider, then wait 30 seconds for your device to turn off. If your device is frozen or unresponsive, force restart your device.
- To turn your device back on, press and hold the side button (on the right side of your iPhone) until you see the Apple logo."
Those steps are from this article: Restart your iPhone - Apple Support Another step you can also take is to keep your iPhone up-to-date, as that can also resolve or stop unexpected issues. The steps below can guide how to do that, if needed:
"Update your iPhone or iPad wirelessly
- Back up your device using iCloud or your computer.
- Plug your device into power and connect to the internet with Wi-Fi.
- Go to Settings > General, then tap Software Update.
- If you see more than one software update option available, choose the one that you want to install.
- Tap Install Now. If you see Download and Install instead, tap it to download the update, enter your passcode, then tap Install Now. If you don't know your passcode, learn what to do."
You can view those steps and more information here: Update your iPhone or iPad - Apple Support Please let us know if those steps help or if you've already tried those steps.
Take care!