Yeah looks like the front wing called it a day and decided to leave the rest of the car. You can see the wing sliding along the ground as Hamilton’s car hits the gravel trap.
It was probably a manufacturing error, but I don’t think Mercedes have clarified exactly what it was. I doubt Hamilton clipped a wall/kerb/etc. since all the drivers at that point (like, all 3) were essentially coasting the lap rather than doing a flat-out, at-the-limit lap.