Hello Alex_3922,
Let's restart both your iPhone 8 and iPhone 14 Plus using the applicable steps below:
How to restart your iPhone X, 11, 12, 13, or later
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.
How to restart your iPhone 6, 7, 8, or SE (2nd or 3rd generation)
1. Press and hold 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 until you see the Apple logo.
You can also find those steps in this resource: Restart your iPhone - Apple Support Restarting can sometimes help address odd behaviors.
Should that still persist, we'd like to get a few more details to help isolate this behavior further.
Was this behavior occurring previously with just your iPhone 8, or did this only start after setting up your iPhone 14 Plus?
Do your messages go to a random contact each time you attempt to send a message, or does it always go to the same unintended contact?
Are you facing any difficulties with receiving messages from the affected contact?
Is this occurring with both iMessages (blue chat bubbles) and SMS (green chat bubbles)?
Additionally, does this occur when attempting to send a message to their Apple ID email, their phone number or both?
Let us know, and we'll keep moving forward based on those details.
