Strange purple spots on red part of plating montipora

[Seagre]

I recently turned of all flow in my tank to add an anenome. Looking down from above I notice my montipora has purple spots everywhere not quite sure what this is does anyone have any clue? The polyps are out 24/7 it's thriving ive just never looked at it from that angle in a long time. I'll also add every other sps even from the same or similar species are healthy with no purple spots.

Parameters:

Alkalinity 8.2
Calcium 470
Magnesium 1350
Nitrate 10
Phosphate 0.05
Salinity 35/1.025

 

[Seagre]

Previous photo was too big re-uploaded.

 

[Bribo12]

Those are the polyps, no?

 

[Seagre]

Those are the polyps, no?

Nope polyps are the same colour as the plates it's only on the red not the green

 

[kevgib67]

Perhaps it’s a superman monti cap instead of a red one?

 

[Seagre]

Perhaps it’s a superman monti cap instead of a red one?

It's not as my mate has the colonies I got it as a frag his are just red I'm aware different lights bring out different results just never seen this before lol. Superman is encrusting type as well this is plate