I'm on a Mac and the issues can be differ between MacOs and Win10. The soundtoys guys confirmed that habit, if you replace a plugin with a soundtoys plugin it crashes sometimes. Another issue is when you put a soundtoys plugin on a track when S1 is running you get an instant crash. Often its crashing on a bus channel. That happens not all the time, but i have this since S1 3.5 or 4.1.
I guess its easy to reproduce when you put 6 different soundtoys on a bus track when something is running and replace it the plugins with soundtoys plugins.