Same experience here, it seems to be hit or miss with asking for anything special with Etihad. I flew to AUH once using a temporary travel passport, which is (or was back then) allowed as per UAE regulation for German citizens. The boarding gate personnel from Etihad in AMS told me "temp travel passport is not acceptable, we will have to talk to Abu Dhabi" and made me sit there until boarding was completed for over 30min, until some guy came up and said he spoke to Abu Dhabi on the phone and they will make an exception for me this time. I was also in business, maybe that helped. But it seems that anything outside the ordinary is an issue there.