look up a tutorial on yt, the combat is very complex

I usually do reflect builds more often, but one of Ghostwalker's flaws is that even auto-attacks can count towards it's dodges, but also rapid-fire arts (Sliding Stinger as a player example). Maybe he or other enemies landed attacks fast enough in sequence to wear it out?

The only other thing I can think of is that there are some enemies that inherently by-pass reflect and ghostwalk-like arts. :p