Clove polyps with singed edges

[gregrock68]

I noticed that my clove polyps have developed singed edges within the last 2 days. All parameters are good, tested everything yesterday. Thought maybe it could be my lighting being too strong but I don't see any signs on any other corals. Has anyone else ever noticed this condition? Any thoughts on what might cause this ? Thx

 

[TX_REEF]

I don't see anything concerning in the photo.

 

[Tub Life]

You do a water change recently?

This is observational only, I haven't done testing to prove anything.

I have noticed singing, and it's usually after I do a water change.
I think it's ALK burn due to parameter swing.
FWIW I use Instant Ocean, and I have read it is high in ALK.