Just experienced another crash syncing on Mac OS 10.13.6 and Ableton Live 10.1.17.
I had an existing session with 2 instances of Scaler with progressions already loaded and saved. I wanted to try another saved session that was quite different from what was there. I tried to load the new session and Live just vanished. After testing on an empty Live session I determined a work around was to remove the Scaler2 instances and load a blank scaler for both THEN loaded the alt chord session and synced one to the other just fine. So it failed while fully loaded but succeeded while empty.