Screen recording issues // screen on top of another screen

Hello everyone,

I am trying to record my screen with the "demo" mode, but everytime i upload the video on the scene i have two screens (as you can see attached).

I've updated my software, i have the last Storyline version and i didn't change any settings, no extra monitor.

I don't understand why, i have a screen on top of another screen.

Can you help me ?