Interesting Acro question

[marie]

In my recent troubles I had a very nice yellow/green acro start to bleach out

This is what it looked like a few months ago


In the last couple of weeks the coral started to regain colour but definitely not the colour it was before. You can see a white branch in the back ground so it isn't a reflection of the lights... this coral is turning purple



Has anyone ever had such a drastic colour change before?

Oh and the tissue is still there so it isn't some kind of funky algae