I had a big nice bulb, one fall the shell crack and out come hundreds of small small bulbs. And the big old bulb was gone, sad.
Why did Hippeastrum split up to hundreds of small bulbs
If the central growth point had died due to rotting by attack from fungus or bacteria, your bulb may have produced the bulblets as a survival strategy, much the same as will be seen in the cuttage method of propagation.
I think this is likely what has happened.
Sylvia, this is very interesting that hippeastrum would do this, too. I have seen it with a local Moroccan wild plant, too.