Same here they will reach in and rip food out of the mouth of LPS but I've never had them eat or damage coral. Skunk cleaners were the worst because they're out during the day and my peppermint are mostly nocturnal. I stopped keeping shrimp with LPS like acrophylia, cynarina etc
I had one attack a frogspawn in quite a dramatic way within 5 minutes of putting him in tank. I dispatched him. Got a second one from same reputable source that was perfect and rid tank of aiptasia. Love him. Eats fish food now.
So...it depends on the individual in my experience.