Clicking the Guardian's Phantasmal Luclinite Mask gives a 16 second buff Form of Endurance XXVI then fades.
From the Test server patch notes ... "- Night of Shadows items that grant Alternate Advancement abilities will now correctly grant the appropriate ability." Hopefully it wil be fixed when live servers update next week.
Endurance clicks are still bugged, as Rank 31 has a bugged out reward: "This passive ability increases your maximum hit points by #1 points." Rank 30 states "by 2800 points."
The original issue for this thread has been fixed. The other issue is currently tracked in this thread: https://forums.daybreakgames.com/eq/index.php?threads/form-of-endurance-xxxi-aa-bugged.290045/