Fiesta beeping when turning

[Ssd_2020]

Hi, I recently brought a used 2015 fiesta with 64k on the clock and everything was fine for about three weeks, however now occasionally when I make a sharp turn or take a right turn at a roundabout I get a single beep noise but with no dashboard warning lights. Has anyone got any idea what this could be?

[Gazcaz]

Nothing on passanger seat causing the car to think somethings on the seat and its the safety belt beep ?