The stealth detection mastery does not allow me to see or target PvE enemies that are in stealth. Mordrem Stalkers, Snipers, etc can stealth and be impossible to see or target. So far as I can tell Stealth Detection only allows me to hit the invisible mushrooms but provides no other benefit to the mastery.
Did you zone out after getting the mastery unlocked? Maybe restart the client? Otherwise you may need to run a repair.
Not affiliated with ArenaNet or NCSOFT. No support is provided.
All assets, page layout, visual style belong to ArenaNet and are used solely to replicate the original design and preserve the original look and feel.
Contact /u/e-scrape-artist on reddit if you encounter a bug.