CRM Cadences recognise auto-responses

CRM Cadences recognise auto-responses

I have leads in a Cadence.
I get an auto-responder reply "I'm out of the office..."

Normally Cadences seems to know that isn't a real reply and keeps the lead enrolled in the cadence.

However, today, Cadences has UNENROLLED a Lead who sent an auto-reponse reply.

What are the criteria?
How do I make it work all of the time?