Hi there! My cymbidium is done flowering and is growing healthy new growth, but it’s older pseudobulb has completely yellowed overnight. Is this normal or indicative that something is wrong with its care?
Your photos are not clear enough but older pbulbs die with age. Most of them, although looking dead, are alive but just covered with a layer of dry sheaths. When they are really dead they get shrunken.
Your plant is still very young. The older leaves will yellow and the remaning pbulb will be covered with those dry sheaths but alive.
Don't worry, your plant is ok.