Hello Julis1957,
Let's use the steps below to make sure that your iPhone is all up to date:
1. Back up your device using iCloud or your computer.
2. Plug your device into power and connect to the internet with Wi-Fi.
3. Go to Settings > General, then tap Software Update.
4. Choose the software update that you want to install. You can choose to stay on iOS or iPadOS 15 and still get important security updates. Or you can choose the option to upgrade to iOS or iPadOS 16.

5. 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 also find those steps in this resource: Update your iPhone or iPad - Apple Support
If your iPhone is all up to date, let's also restart using the steps below:
1. Press and hold either volume button and the side button until the power-off slider appears.

2. Drag the slider, then wait 30 seconds for your device to turn off. If your device is frozen or unresponsive, force restart your device.
3. 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.
That process is also covered in this article: Restart your iPhone - Apple Support
Updating and restarting can sometimes help address odd behaviors.
Should that still persist, you'll want to reach out to Apple Support so they can look into this behavior further: Contact - Official Apple Support
Take care.