I picked this up about a week ago at a local "pet" store. Terrible light and water flow there so I was thinking it would stand up I'm my tank, but it doesn't. It puts out polyps and seems healthy over all but it won't stand up.
IME these corals like a lot of chaotic flow. Then again it might just be pouting. They can be very temperamental sometimes too. As long as your parameters are within reason and everything else looks good it might just be a matter of time. Maybe give it another week or so and if there's no change you might want to move it to a different spot. GL.