Forced updates did happen (only way to play the game if Steam was aware there was one available - and God forbid you had a slow/flaky connection - no gaming for you today, not even through Offline Mode !).
Combined in at least one instance with the new version not being able to load the old multi-hours save, and no rollbacks, so hopefully you manually backed up the whole game ! (At least the devs fixed it in a patch after some days...)