Can't change andy prefab ARcore 1.2

Hello,

I'm having a weird issue with ARcore 1.2 if I change the ARcore Andy prefab to either a different prefab (a plain 3D cube) or I add the cube into the default andy prefab it when linked the anchors together it claims to have found the anchor when it hasn't, the location of the anchor is at 0,0,0 and it doesn't appear anywhere else in the scene, I'm confused how adding a cube to the andy prefab could break it, any insight anyone has would be greatly appreciated.