I have a question about the documentation

I read documentation

Secrion " Base Read-Only System"
And i have question.
What are the reasons for the overlay version to be considered damaged?
How does the system decide to roll back?

Here says "Updated or modified systems enter a probationary period (default 30 minutes) during which time an app or framework daemon failure will result in a roll-back to the previous “good” system. "

Command call
update -g

Will solve this problem?

Embed your app to legato.cwe is the recommended method