I also have a zigo that was given to me as a gift. It was not in the best of shape and the young bulb (after the flowers were finished) it taking a long time to grow and form a bulb. Do they start growing a new growth before the young growth (that finished blooming) is mature?
Wren, a picture is always helpful. Mine blooms on new growth before the pbulbs form. It will bloom and then send out new growth from that point..Maybe I'm not answering what you ask.
In my experience, zygopetalum spikes and new growths appear closely timed, and the new growth continues growing, mo robustly, after the flowers have faded.