Guild Wars 2

I was just wondering if it is possible to code it so epidemic does not target invulnerable targets, and thus waste the target space that should go to mobs that can be damaged. This can be seen easily in the Xera fight, because often the projectiles go to the orbs that spawn mobs, without doing anything, or the mobs that are still invulnerable for a decent duration. Plus, epi likes to miss quite a lot in the Ark fight (the CM part when the phase splits and new mobs come in). If it is possible, is there a reason why it isn’t implemented, because it just seems odd that a skill that you cannot control the targets, can target something that is immortal. Thank you, and any player feedback is nice too.

And while at it they should fix the undocumented and unjust nerfs to epidemic on wvw.
Epidemic doesnt work on cannons,doesnt work on siege.
And yet it goes and hits the supply stash on camps/objectives.
And according to observations it gets blocked by people with resistance on.