Hello CassieZ3,
Let's use the steps below to restart your iPhone:
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 A restart can sometimes help address odd behaviors.
Should that still persist, do you experience the same behavior if you record a new video?
Let us know, and we'll keep moving forward based on your result.