I had a condy like your's that moved around all the time. It finally found the slimmest of spots on a powerhead and was " blended up" over nite. I awoke to a cloudy tank and bits of anemone everywhere... I covered all possible problem areas with filterfloss and zip ties. you'd just have to keep up cleaning or replacing them. I have a rose anemone now thats found a niche and has never moved , but i'm leary of removing all the covers..
GOOD LUCK!