Text message response that I did not write.

A message response was sent as if from me but I did not write it. It was in context to the message sent to me but not necessarily how I would have responded. When I discovered this and alerted the other party, we both found this to be very disturbing. Could Siri have impersonated me? In the Siri & Search settings, there is “Automatically send messages” as well as in every app, “Learn from this app”. As I do not use Siri, I had not looked at the settings previously. They all seemed to default as enabled on my phone. If this is the default, I find it troubling.