the mechanism of avast auto sandbox

I have some questions and problems that the mechanism of avast auto sandbox
First. What situation it working?
Second. How it think that program is the malware?
Third. Where it storage and running, is it safe?
Forth.
In A computer. avast think the program as the malware
In B computer. avast say it doesn’t have enough evidence.
What is it problem?

Avast blog

https://blog.avast.com/2012/03/20/autosandbox-why-are-you-annoying-me/