Guild Wars 2

I just spent some time trying to bypass the “An apple a Day” particular bug on my thief, and after 4 or so tries it seems I’ve found a way. As thief is mainly a single-target class, I was having difficulty killing all the guards one by one before the commander reaches 25% (it seems that’s when the bugging starts), so I set up some traps. One or two guards still were not killed by me directly. They were tagged by me though.
And it worked.
So perhaps it’s enough to tag all of them, not kill.

Race: Human (any)
Gender: Male (any)
Class: Elementalist (or any other class that can use a staff or a scepter)
Weapon: The Crossing, Pact Scepter
Issue: Strange shader/texture appearance

Both weapons look as they should when I log in, but as soon as I open the Hero screen – the Pact Scepter (or the chain part of The Crossing staff) turns misty-white.
This only occurs when shaders in the graphic options are set to High.
Also, I’m not the only one seeing this glitch – a friend of mine is playing GW2 too, and he confirmed seeing my weapons change color as I switched shaders quality or opened the Hero screen. Our computers are completely different (I have a stationary PC and he has a laptop), but we both run Nvidia graphic cards.
Also, I play with all graphic settings maxed and I never had any performance or visual problems except for this.

Same issue with The Crossing, and also Pact Scepter. I’ve noticed, however that this happens only when you have shaders set to High in the graphics options. When they are on Medium, the bug disappears.
I’m running GW2 on the highest graphic settings since I started playing it, and I’ve never had any problems except for this. Tuning down shaders is not and option, since it will make everything else in the game look bad.
Any advice on the matter will be most welcome