I have an iPhone 6 plus, why does Siri sometimes say What triggers this action?

[iMore Question]

I have iphone 6 plus. Seri will say

what triggers this action?

 

[kch50428]

Re: I have iphone 6 plus. Seri will say

About Siri - Apple Support

You have "hey Siri" enabled, and it heard something close enough to that to wake up and respond...