I have two bifucatum Netherlands, one 8 or 9 years old, the other only a bit over 1 year. Never had any problem with the older one that is mounted on a piece of wood, and the newer one shares exactly the same conditions except that it is mounted on a redwood frame with moss, purchased specifically for stags.
The newer one continues to drop healthy green fronds. It is hanging on my patio next to the older one, with nothing coming in contact with it to cause the fronds to break off. I do see new growth routinely, but I find maybe a frond or two per week that have fallen off. The older stag thrives and continues to grow.
Anyone have any idea what's going on?