An update to MS's experience for her return flight on Etihad in late Sep with her AAdvantage number visible in the booking on the Etihad site -

She (MS) had not earned any miles on AA from her outbound legs (to the US in Aug) on Etihad.

She upgraded to Business Class for the BOS-AUH segment of her return. The rest of the segments in her itinerary were on Economy. She did not get any miles on AA for the Business class segment either. When contacted about the missing miles, this is how AA responded -

"... your recent transaction with Etihad Airways was not eligible for mileage credit based on their earning rules. To review the mileage earning details for this AAdvantageŽ partner, please visit aa.com/earn"

We have reviewed aa.com/earn many times to understand the Terms and Conditions for earning miles but it is not clear why earning miles is denied.
What exactly are the earning rules on Etihad that the airlines seems to only deny miles awarded on AA? Where is the wording and where are they listed?

AA has no answers for MS's query. We would consider it misleading to think that Etihad is any kind of airline partner for AA.

This screenshot from aa.com/earn shows the miles earned on AA from flying various classes on Etihad. If Business Class doesn't earn miles, what would?