When I walk in a zone with Elysian Illumination active, neutral mobs, like deer and rabbits, receive damage. The description of the skill says, that it damages enemies and heals friends. I think the skill should have no effect on neutral mobs.
I think that is the intended effect - you as the caster need to be cognizant of what might hurt. Just like if you have immolation active. Going to move this to feedback as it seems like a request/suggestion. If a developer thinks it should be altered that would be the better place to discuss it, IMHO.
I would hold a middle ground. Sure, Immolation is FIRE and should not discriminate between enemies and neutrals and could even be questioned for not doing "friendly fire" on allys. But Elysian Illumination is essentially sunlight. It should hurt undead always. But living neutrals? IMHO not.
The difference between Immolation and Elysian Illumination is, that Immolation is an aggressive spell only, while Elysian Illumination is both beneficial to friends and aggressive towards enemies. I would think that mobs that are neither friendly nor enemies should be unaffected by the spell.