Merulina on my Trumpet Coral?

[naturebatslast]

I was moving a piece of trumpet coral and noticed what looks like a small patch of Merulina/Pachyseris type-of-thing. This is weird be cause I haven't owned any Merulina in a few years. The patch although a light tan, has calcium skeleton with small, long fisures or septae, with a few small green dots. Thought it was a striped mushroom at first, but after seeing the skeleton....I'm thinking otherwise.
Any ideas?