The former Dota 2 professional player He "Inflame" Yongzheng, who recently recalibrated at just 10 MMR, got his rank fixed. According to Chinese Dota In A Nutshell on Twitter, the game recalibrated him once again, and he got back to 8k MMR.
At the same time, another Chinese player, Deng "Dstones" Lei, encountered the same issue. He was losing a 1k MMR per game, disregarding victories or losses. The Twitter report appeared just hours before the update on Inflame, so it's unclear whether Dstones got recalibrated back as well.
The second appearance of the bug confirms fans' fears. For the casual players similar bug will cause much more issues. Grinding from the very bottom might take a long time, and playing among unskilled players might label you as a smurf. Inflame had a hard time telling people at the lowest ranks that he's a former TI participant.