We looked at this for version 11 CCX.
We had a CCX customer who wanted to use the dialler for Business to Business calls. If the company they dialled answered with an IVR the dialler said this was an answer phone and dropped the call.
We did query this with our Cisco SE and was told there was no way to disable answer phone detection.
I have not seen anything that says this behaviour has changed in 11.5 or 11.6
Graham