[2021] Match cancellation after the first round

A few days ago my team started a match and steamrolled the opposing team in the first round (flawless round) and during the drone phase of the second round, while we were discussing our plan for the second round we got the message that the match was cancelled. This was really weird, because we played the first round with everyone present and the guy only left after the end of the first round. This was disappointing because, we were confident in our victory and were cheated out of it.

My question is: What are the exact rules of match cancel or was this a bug?

Match ID: 50fb18b1-fa92-4e91-8abc-bf838d85172d
Match-2021-03-18_22-18-01-1˙