Hi
Ive noticed that stuns and knockdowns do not affect NPCs for the full duration. I have stunned mobs for an expected 3 seconds only for them to recover almost immediately. Same with a 2 second knockdown.
Also, after having finally made Juggernaut, the Sigil of Sanctuary bugged. After the invincibility wore off I was left with a glowing graphic around my hands and the kill counter would not restart. The graphic disappeared after maybe 20 seconds but the sigil was still bugged. The effect is largely useless. Its duration needs to be longer, less kills required or have an on hit grant 4 seconds of retribution; something, anything.
Stuns and KDs vs PvE
Sigil of sanctuary