Screen mirroring activated when I haven't enabled it

Hello, I have a MacBook Air M2 2023. A few days ago I created several sessions on the device and since then, when I log in sometimes (with password, TouchID or Apple Watch) I encounter the screen Mirroring logo activated in the menu bar and the screen size not adjusted. I can't click on the apple in the top left-hand corner, but I can interact with the control center in the top right-hand corner. Has anyone had this problem?

So far, to fix this bug, I completely disconnect from the current session and connect again and the problem is solved but I'd like to understand where it comes from (if I've been hacked...).

Thanks in advance.

PS : As you can see on the attached, the top of the window is slightly cut. In the display settings, there's nothing to stop this screen sharing