We've had phosphate issues for 2 years now, I think we're finally getting things under control! What I've learned recently is that high phospates can make it harder for corals to absorb calcium.
If this is a new development, it's possible the stress has caused some issues with them, but wait for more advice.
Our phosphates have been much higher than yours for quite sometime, we just recently got them down to 2, and I'm seeing a big difference in some of my corals.
Another possibility for recession is lack of direct feedings and/or improper or old lighting.
Good luck!