The only experience I have with ornamental alliums is with drumstick alliums (Allium sphaerocephalon) but I'll attempt to help.

There's only a couple things I can think of to prevent them from sprouting in the fall.

1. Buy new bulbs from a new source, if you haven't tried this already and if it's possible.

2. Try digging the bulbs when they are dormant and then wait until around now to plant them (when the ground is cold but not frozen). Waiting to plant them until it's cold should give them enough time to grow roots but not enough time to grow greens. This might force them into growth in the spring.

Rodney