360° Ground Slam doesn't hit enemies in front of player

Being a Standard enjoyer, I thought I'd try to make the ordinary Ground Slam like the Vaal version with 360° coverage. Easy enough with Ground Slam of Earthshaking + 2 × legacy Rapid Expansion + legacy Ground Slam angle helmet enchant. You get a nice full circle around you like with the Vaal skill, but enemies directly in front of the player are completely unaffected.
Have Resolute Technique so it's not an accuracy thing, and it's immediately fixed by e.g. dropping one of the two jewels to reduce angle, but then it's not a full circle anymore. :(