Sidecar turns on by itself on iPhone
I recently noticed that my phone turns itself on and lights up when the screen is locked. When I open it, it tells me that the Sidecar app is on. As far as I know Sidecar can only be used on iPad and Mac. I did not download this application on my iPhone. However, the screen of the Sidecar application is pure black, it only displays the "Donе" option in the upper right corner. I checked and in fact this application is not installed on my iPhone. I don't understand why the app turns itself on like this.
Please, have in mind that I do not own an iPad device and there are no iPad devices near me, only Mac devices.
Is this a bug or something else might be happening with the iPhone?
iPhone XS, iOS 15