Statisticly every 500 jumps you can expect malfunction of your main canopy. Of course for one of us can have thousands of skydives without cut away and another one can have problem on the first time. Sorry, that’s life 😉
We have to remember that higher loaded canopies can react more violently. Downsizing means more risk during common landings and more risk when your main canopy doesn’t open properly. Here you have main parachute malfunction video. That’s line twist, caused by unstowed toggle (bad packing job).