Why is glow limited to only 4 entities?

[meszaros-lajos-gyorgy]

I have a custom npc that has the following event to trigger glowing:

// npc
ON GLOW {
  if (^$param1 == "on") {
    HALO -ocs 0.8 1 1 30 // [o] = active, [c] = color, [s] = radius
  } else {
    HALO -f // [f] = inactive
  }
  ACCEPT
}

All npcs are in the group of bots so I can send them events all in one go.

sendevent -g bot glow on

will only make the first 4 entities get halos, all others will stay without a halo:

What is the reason for this limitation and how can it be increased?

[meszaros-lajos-gyorgy]

It changes depending on where I stand, sometimes a guard only gets half a glow:

The behavior of HALO is not documented: https://wiki.arx-libertatis.org/Script:halo
The source code might give info on how it works: https://github.com/arx/ArxLibertatis/blob/master/src/script/ScriptedIOProperties.cpp#L445