Certified GKH Gardening Expert
This isn't too common, considering that the offspring from bulb are identical to the parent. If these were from seed, then you can expect many of them to be quite different in flowering than the original parent.
I would check a few things:
Make sure that the pH and nutrient levels are within range of about 6 to 7.5, and make sure that the phosphorus levels are somewhat high for flowering. Too much nitrogen can cause flowering issues.