Guild Wars 2

Today, before WvW reset, I have thrown almost 80 rare staves in the Mystic Forge and I’ve obtained 6 exotic. My server was in the 1st position and I had high World bonuses, included Artisan bonus (which increases the chance of crafting critical success).
After WvW reset, I have thrown 100 rare staves in the MF but I haven’t obtained any exotic.
Is it only RNG in action or does Artisan increase even the exotics drop rate?

I think “crafting critical success” only relates to getting bonus crafting experience when leveling your craft. I don’t think it has anything to do with Mystic Forge. I may be wrong, but you probably were just lucky one day and unlucky the next.