Has anyone's TVS Jupiter has been moving like Tarzan the Wonder Car

My family had bought a tvs jupiter in the year 2022 and last 2 years it has been acting a really odd. The problem occurs when the scooter is used after a period inactivety mostly ranging for a 8-12 hours or more than day. When engine is started by inserting and pressing the start button the vehicle begins move forward without any acceleration given by me. This goes on for a distance of 10 - 50 m and then control of vehicle returns to us. Rain also shortens the duration required for the phenomenon to occur. This is a little scary but it has been occurring from two years and we shown tvs service center with no avail. Has anyone had similar problems or does anyone has any solution