I have a colony of rhodactis mushrooms that if they are the least disturbed will spit out what looks like its stomach (white noodle looking things). I don't think it is anything to get too concerned about as long as it isn't happening frequently.
As for the brown stuff, I have seen some LPS corals spit out what looks like a brown string like film. If I remember what I have read in the past correctly, it is a way for corals to expel excess, I know this won't sound right but, nutrient intake. Not so much food, but things they have absorbed from the water. Someone may have a more accurate explanation though. Like I stated above, I don't think it is something to worry too much about as long as it doesn't occur frequently.