Acro bleaching at base

[AWarnick]

The base of this acro is now shaded by the upper part and i don't have the ability to add more directional light from the front yet.
Is the bleaching which is happening here something I need to frag the rest of this coral to prevent spread or is this natural with shading?
Are the brittle stars you see here eating the flesh that has died or are they any concern?
Any help appreciated