I lost a match because of a timeout from my side. However, it looked very strange and the way how the timeout occurred looked more like a MTGA application bug or a foul play from opponent's side (or both).
The story is quite simple. I played on the Bo1 limited ladder a VOW quick draft match against Ozon#26468. Quite in the beginning, I noticed considerable flickering of my cards in play and in my hand. It looked like if the opponent was looking at my cards hovering their mouse over them, but selected cards changed very rapidly. It stopped from time to time, mostly during opponent's turn. It was quite annoying and made concentration difficult, but the match went on. I think I had upper hand and was quite close to a victory.
However, in the decisive turns, flickering intensified and most likely because of that, my application started to be very slow responding to my inputs. It was very difficult to transit from on game stage to another and I had to mark attackers and click on the next stage button many times to get any reaction. Like if processing on the onhover event had higher priority. Initially I thought the app just got crazy, so I made a quick restart of it. I returned to the match successfully, but this selection flicker continued and I was locked out of the game almost completely. Even if I pressed buttons (like "Next step"), the button disappeared for some time, but appeared again after several seconds like if it was never pressed. Ultimately the game announced that if I don't react, I would lose the match, which despite my efforts to use any possible UI element eventually happened.
I lost matches on rare occasions because of connection issues in the past, but this didn't look like such a loss. I saw no issues with my connection and the game restarted and reconnected to the match quickly without any problem. It might be a some kind of a bug, but the game log shows a massive amount of onhover events which is not a typical situation.
I have no idea how these are produced and how the application should react to them. But if there's a way how to trigger them easily by a deliberate action causing a DoS attack on the opponent, you should seriously think about a fix. It is up to you to decide if it was a case in this particular match. It might be just my impression, but it looked like the opponent was well aware of what they were doing.
Please check the attached logs (before and after restart).

Cheers,
--Tom