I have heard the reason for limbs to just fall off of the capnella is that your PH is too low. I had the same thing happen to me so I raised my PH by using Kalk and it hasn't happened since.
I can prove you wrong. Here is an article from garf, if you dont know garf, they are professional reef keepers.GARF stands for Geothermal Aquaculture Research Foundation, and they keep their tanks perfect, and they said that their capnella droppes frags
off. Heres what they said
You can see the plug this coral is mounted on. It is a very fast grower. Once it reached its current size, I noticed that it was dropping frags
off of its branches. There are many of its babies all over the tank.
One of the best growers of all the corals. It has been propagated many times. I have found that it recovers better from propagation if it is pruned, rather than taking most of the head. It also drops off branches at this size. If you look closely on it's right side you can see a new baby attached on the Aragocrete rock next to it.