Autosandbox default is “ask”. Behavior Shield default is “auto”.
Autosandbox settings aren’t related to File Shield actions (which default are sent do Chest).

If a malware is detected in an on demand scanning, File Shield will control it (send to Chest).
If you try to run/execute the file, the Autosandbox will act “before” (as it is a part of File Shield).

Some users use that with very careful do to false positive being moved automatically to Chest…