All 'hostile' entities, that is:

• Spiders
• Zombies
• Skeletons
• Creepers
• Phantoms
• Enderman
• Witches

Are placed in a team called 'hostiles' with team colour 'red' and a glowing effect is applied to them.

The issue is that any entity with a glow map, or whatever you would like to call it, or should technically call it within Minecraft lingo, do not glow with team colour, except faintly in circumstances I have yet to determine the pattern to, which can be seen in the attached photos as the pink spiders, in all other cases they glow only white.