Darcy, if this is a back-bulb rather than new growth, it is not unusual for those old leaves to brown and fall off. This appears to be an Oncidium-like plant, and though I have never grown a Zygo., my Cymbiums/Oncidiums will lose their older leaves.
drdawg (Dr. Kenneth Ramsey)
The reason it's so hard to lose weight when you get up in age is because your body and your fat have become good friends.
