Hey there, This is something I've recently experienced and this seems to be the only avenue of reporting the glitch/bug/behaviour. In the strike/Nightfall The Disgraced, Guardians can throw grenades or cause other lasting AoE damage in a specific area to force enemies out-of-bounds. Especially, this can force a Champion Barrier servitor to move out-of-bounds and despawn or be unkillable, thus resulting in less than platinum rewards for completing the Nightfall. The issue can be replicated by throwing grenades at the area indicated in the image, especially Solar grenades thrown by Warlocks, immediately before being able to access the area (I.e. before clearing enemies in the current area and the lasers at the door turn off). This has been used to sabotage runs for other players.