I think I have the same issue like described here on this topic. I added 5 layers and tried this configuration multiple times and everytime I ended up with this shutdown error. There seems to be something wrong with saving and restoring snapshots. Some information I wrote down in this topic Multiple layers + external midi controller + stage piano? - #29 by pianissimo
Unfortunately at this moment I have not the time to trace a little deeper (check midi , audio routing, logs) on this bug. But hopefully now there is some information available. @ricard thank you for registering this bug. Is this a high prio bug? Because I think backup and restoring configuration should be something to take special care on it.