I've had this problem myself. It only seemed to occur in a large container which was pretty crammed with layers of different bulbs, and I concluded it was because there's insufficient soil room for the temporary planting placed in the top. Certainly, when I emptied it out, it was quite difficult to get the larger bulbs out, they were pretty much wedged together, and there were a number of offsets taking up space too. I have other containers that do have bulbs and summer planting, but it'll only be a few bulbs beneath.

You had narcissus/daffodils in the pot though, and they do exert an allelopathic effect on some plants.

I've had this problem myself. It only seemed to occur in a large container which was pretty crammed with layers of different bulbs, and I concluded it was because there's insufficient soil room for the temporary planting placed in the top. Certainly, when I emptied it out, it was quite difficult to get the larger bulbs out, they were pretty much wedged together, and there were a number of offsets taking up space too. I have other containers that do have bulbs and summer planting, but it'll only be a few bulbs beneath.

You had narcissus/daffodils in the pot though, and they can exert an allelopathic effect on some plants, though I use a few dwarf daffodils in pots with winter, then summer bedding, and haven't experienced this problem.