I can't really make out coloration on your pic. But I can say that I have found many chalices to be among some of the most light sensitive corals I have kept, even lower in the tank under my 6 bulb T5 fixture running 39w ATI bulbs. I don't know anything about your LED, but a higher powered unit could easily scorch a chalice I would think.
If it's losing color I think it's a reasonable precaution to move it to an area with less light, even partial shade like you would find under a ledge. Give it some time and move it out slowly. Where do you have it positioned now and what are the details on the lighting? GL.