GM Blog : Coming Soon: "The Battle of Crimsonwood Keep"

Glitches are a definate.

NLC had boomers.
The mansion had the Loki Boxes (though that may not have been a glitch per se)
Phantom forest had bigfoot

Boomers weren't a glitch. They were merely a good idea that was used to people's abuse; so Nexon had to patch that (the whole Poison abuse issue).

Bigfoot wasn't entirely a glitch either- the fact it was poisonable was one of Nexon's intended ideas- Prose even seemed to embrace the idea of it when prompted about the use of poisoning it; but when Bigfoot killing abuse became a problem, it got labeled as a glitch.

The glitches that really come to mind with NLC I can think of are the Phantom Forest-Crimsonwood Mounts area are the messed up Knockback animations and god-modes; and in addition, the whole issue over Pirates not getting the quest and the pirates' version of the quest not working with Urban Warrior quest oddly.

My guesses for what the Party Quest's interactive-storyline, given in mind it could be a "gradual effort that's said to make things better but never really does" or a "temporary solution where the problem isn't resolved and may return to be able to stop again, but the story can move on" is that you stall/temporarily stop the attack on New Leaf City sounds like an objective or the whole thing in it's entirety. With that in mind, here's what I'm going to guess-

• The boss really COULD be the 4 Twisted Masters; though you don't quite kill them but defeat them to get them and the troops to delay their plan by having targeted the leader and causing a temporary halt, yet they still hold control.
  
• You don't even see the 4 Twisted Masters- at all; it really could just be stopping the onslaught of the Versalian soldiers with a few nasty bosses at their disposal.
  
• Interestingly, here's one theory possibly involving the either of the above: what if your objective- in addition to stalling the troops, was to "weaken" the Versalians' control over the Keep with something- ending with a "it helped" and could move on in the story; however, it doesn't truly resolve out.