We’re all playing the heck out of this game
But one of the stumbling blocks seems to be the recurrence of invisible Skill Challenge NPCs and broken events. These all get cleared up at server restart and then break at some variable (and under variable circumstances) thereafter.
While you continue to explore a permanent fix, would you consider nightly server restarts? Maybe an hour or two before local server prime time, and with enough notice that people don’t get themselves caught in the middle of a dungeon.