Gknight Temporary Blindness?

Ill be standing in the gknights .. the last turn before barons, centered in the hallway just outside the room with the 2 green spawners to the S. I'll kill a few or a dozen knights.. then all of a sudden, they just dont see me. Last time none of them saw me, this time 4 out of 5 didnt see me. As soon as I move, they see me again? Its happened both times in the same spot +/-. Havnt noticed this anywhere else in game.. just thought it kind of unique.

I am not 100% sure of the maths behind this but whether a character can see another character is driven by:
1) Stealth - higher mod means less likely to be seen
2) Perception - higher mod means more likely to be able to see
3) Distance - longer distance means less likely to be able to see
4) Light - lower light means less likely to be able to see
5) Speed - lower speed means means less likely to be seen

In your case the two characters are the same (you and the greenling) so it is most likely driven by distance and light. Light may be difficult to judge precisely as it depends on distance from lamps and players with light on.

I had light on at the time and was on fast I believe. Out of the 4 that did not see me, two were beside me.. the one that saw me was at a great distance (6+ tiles).

The part that strikes me as odd is that they all saw me from any position from any tile initially. Then after killing a dozen ish of them, they suddenly couldnt. I wasnt paying enough attention to how many died and when though. Perhaps the first four saw me, decided to attack and paused because they couldnt reach me and simply never exited their idle state? What triggers an NPC to look for a character and find a target?