The former professional player He "Inflame" Yongzheng did a recalibration of his Dota 2 account on stream. Before that, he reportedly had an 8,900-9,000 MMR. But when Inflame finished the process, he saw a score of 10 MMR.
According to Redditor Livid_Ad_7244, the ex-pro started in Immortal rank but faced Legends after a few games. Going further, his MMR was seemingly getting lower and lower with each new match. This should be some kind of unknown bug, as here are his latest games:
Inflame reportedly continued playing on the lowest ranks, telling everyone he is a TI player (reached top 3 at TI7 with LGD.FY), and nobody believes him. Some fans blame the new heroine Muerta for this incident as he picked her for some initial recalibration games. It is possible that the new hero is bugged, somehow drastically affecting the outcome.
Patch 7.32e came out on March 6, adding Muerta to the game, along with the Dead Reckoning chest and a related mini-game. The developers also changed the Turbo mod, several items, and adjusted meta heroes.