Xin Zhao's bugged Q isn't game breaking enough for Riot.
In this particular case Xin Zhao's Q doesn't knock up if the target isn't moving at the time of the third hit. That's definitely a significant bug, but it's not crippling him and the fix involves code changes
If this were a bug where Lee Sin's Q didn't mark the target hit, or Zed's passive was dealing damage which stopped at 1 hit point before death, there would be a hotfix out yesterday. (Based on prior examples from relevant player-base size and glitches/malfunctions)
Yeah... No.
