Why does my iPhone 15 make random calls out of my contacts list

This is weird. Please force restart your iPhone to see if the issues persist

1. Press and quickly release the volume up button.
2. Press and quickly release the volume down button.
3. Press and hold the side button.
4. When the Apple logo appears, release the side button.

Does that happen when your iPhone is not in your pocket or in a bag? If the iPhone is laying on a desk, for example, then does this issue happen? Does this only happen to the last person who texted you? Does this happen to the last person who called you? Need more details from you to provide a proper response to your post.

Axel F.