Won the Game but shows I lost

I have been conducting tournaments from the past 35 weeks in lichess but this problem has been cropping up from the past 4 weeks or so and nothing has changed much. Many of my students complain that the game that they won was acually shown as a loss and they eneded up getting zero.

Please check the losses by this player 'Jagrav10Srinivas'. It could be helpful.

Can you link the games ?

All I see is many many resignations in less than 10 moves or games where he didn't move at all...

IT EVEN CAME FOR ME