Update this was reproducable also with Scaler 2 Audio used as an effect. It crashes just when hitting the first blocked key marked X.
Win10
Reason v. 10 64 bits
Load up Scaler 2 as an instrument
Choose scale G minor pentatonic
Activate key-lock
Start playing around on the keyboard. When hitting a blocked key it crashes.
Reason itself does not crash but recommends a restart to ensure stability.