Usually this is an eyesight or pin blur problem. Is the sight picture, pin and target crystal clear at 30yds?

Could also be some torquing issues at the grip that are showing up...or maybe the deathgrip on the bow leading to steering the arrows at that distance.

Archery is a self fullfilling prophecy if one ever existed. In other words if you assume you will shoot a wide group at 30yds....you will!