Overexposition issue with Olympus Trip 35

I bought an Olympus Trip 35 camera and shot my first roll with it to see if it is working. Most of the photos turned out as expected but there were four that looks like this. They are overexposed, most probably because of the shutter being open for too long (i suspect mechanical imperfection) but what are these patterns that look like lightnings? Does anyone know what caused that? All photos were shot in automatic mode.