I had read on here before that a member had a montipora that had stopped growing and asked what he could do. Someone else wrote that if he would trim the tips back, it would jump start it. My montipora had tips that looked just like yours in the pic. I trimmed mine, and in a short while, it started growing again. I think mine had just a bit of algea growing on some of the tips, so it helped to trim it away. That has been several months back, and my montipora is still growing.