Hi scotty,
Yes this is normal I have tons of
pulsing Xenia in my tank
No you do not need to cut it or clip it if you don't wish to. What I usualy do is find some nice size peices of live
rock rubble and place them all around your colony the stalks do as you say stectch out then eventualy lean over and the little spot that looks like a bite or gouge will usualy attach to the rock or what ever surface itr is near.
I find by placing rocks all around my colony that when the new rock gets covered with xenia I just reach in and pull it away from the main colony and either trade it or sell it to fellow reefers in my Local Reef Club ortrade it to the LFS
Good luck sounds like all is going well.
Clay