Interesting. Havent heard of that situation but i rarely hear of engineer gobies. It makes sense.
Once it gets healthier, it may potentially injure or kill them. Some cases of lta's killing fish. Not as much as carpets though.
Honestly I might get rid of them. While they are reef safe in the fact of not harming anything, they are sort of bullies. They enjoy burying my feather dusters, travel to the other side of my tank to spit dirt in my goby/shrimp's hole and keep uprooting my anemone. They are a nice playful fish, but their playfulness is making my other inhabitants suffer. All I need to do is come up with a good trap, probably the bottle one

