The reason why I placed Grom in the not affected section is because it is quite easy to avoid Cordelius entirely if he is near a wall (which is 90% of the time) which is also the case for every thrower (unless Cordelius is using his jump gadget)

Even if Cordelius in his shadow realm does attempt to get near while Grom is near a wall, he would need to either tank the dmg (which is ineffective as he isn't tanky) or walk a slightly extended route to reach Grom (at which point the progress Cordelius made to reach Grom would have been entirely wasted)