Bubble bursted

[Alfredomeinhardt]

I had this coral for more than 5 years now.
A few months ago (maybe3-4) it developed a bobble on one side. Today I came back from vacation and the bubble bursted (see the pictures).
Anyone knows the reason and if I should be concerned??

thanks

 

[blaxsun]

There's not really a lot that you can do. It should eventually grow over at some point.