Branching Psammacora - shaded part turning white

[jisc]

I’ve had this piece for a couple months. Slow grower so far but has expanded on frag plug.

I glued at an angle and underside that gets no light has turned white. Anything to be concerned about?

I’ve considered standing it up straight

 

[DSC reef]

That looks like tissue recession, possibly from the algae on the rock.