if it helps, it happens randomly after a fisher has started fishing, then decides to move to another spot. They then move far right, off the map, and cast their line.
Its like one of the available fishing spots is off screen, or something.
Then the fish gets stuck when being pulled against the pond side, and jumps back. After this happens a few times, the fisher leaves a negative review, then exits.
This happens frequently for me. It is like, every time I boot the game up, I will see it happen within 3 game days. But, more often, the first game day.