Monti damaged

[Joker Corals]

I woke up this morning and found out my kongpao Monti are damaged. Did anyone know what thing can cause this type damage? Flat worm ? Montipora eating nudibranch?

Fish species:I have tangs, clown, and banana fish
Also two angel fish
Clean up crew i only have hermit carbs and snails

 

[nautical_nathaniel]

Have you dipped the coral recently?

 

[Joker Corals]

Have you dipped the coral recently?

I dipped all the new coral. This frag I have for over 5 month never happened before