The parent company attempted to make claims on works I'd done on my own time. I balked. I declined to sign their employment contract, which stipulated any ideas I'd come up with, devices I made, or code I wrote, on my time or theirs, belonged to them.
You called their bluff. Good for you. If it wasn't a bluff, you'd have heard back.
Much of this nonesense is thanks to lawyers who're trying to tilt agreements to be maximally advantageous to the corporation. It's easy and inexpensive to thrust a one-sided agreement in front of people. Most people will just sign. If you push back, it's no longer an inexpensive process for them to pursue the issue.