Oh that's probably the issue then. It didn't happen every time I tabbed back and forth between windows, but it's quite possible that could be the culprit. I'm on Windows 10 Home, if that helps.
I did quite enjoy the game (for the most part) and finished though. It was a very interesting/different experience as to what I was expecting initially, and I liked how it surprised me. I'm hoping to review it in more depth soon.