Bungie has disabled the Trials of Osiris PVP mode after a portion of the game's community discovered a way to fix matches and farm-free flawless cards.
Destiny YouTuber Lunarated helped uncover the match-fixing when he noticed teams of players using the Hakke emblem in-game were throwing matches he played against them. After researching the emblem, he found that players in the China/Hong Kong region were using the Hakke banner to signal other players they were involved in the match-fixing ring.
To execute the exploit, a team of three must queue for Trials using burner characters. Two members of the team wear Hakke emblems to show their intent. If the team runs into another team without the Hakke emblem, it backs out, suffering no penalty as the members are all using burner characters.
If, however, the team matches with another bearing the Hakke emblem, one player from each team messages the other via Steam and rolls a die in the chat. The winning team then switches to their mains, and the losers back out of the game. This would earn a win on the winning team's main character's Trials cards, while the losers face no penalty for leaving as they're still on their burner characters.
Repeating this method allows players to win seven matches in a row and net flawless completions, gaining access to the Lighthouse and the best rewards available in Trials of Osiris.
Although the exploit started in China and Hong Kong, it now appears to have spread around the world. One analysis showed that nearly half of all Trials players went flawless in the week in question.
Following its decision to cancel the rest of the week's Trials, Bungie has re-enabled the Lighthouse for players who earned flawless cards legitimately or otherwise. It has yet to make a statement or address the possibility of Trials returning Friday.