I recently purchased a hammer coral and it started to exert a type of waster. It has been around 3 days since the coral entered my tank, and I think it may just be giving off waste from being stressed, but I’m not sure. Anyone who can tell me.
I believe you're asking in your title about brown jelly disease(?). I've never heard of (any color) glue disease.
The coral in your picture is pooping. Nothing to worry about there.