I'm also wondering how this happens.

What I've been doing: pick up a call, wait till I hear the words "green slip" or "Inverse assignment". The INSTANT I hear "Inverse assignment" I hangup the robo call. I call scheduling, sit on hold for twenty minutes, and when I finally get someone on the phone it's already gone.
I saw people in another thread say it can go IA an hour before they send out the robo calls and now I'm even more confused.