Qatar Airways decided to ground their entire 787 fleet (all 5 of them) around Doha lunchtime on 17th January in compliance with the FAA and Qatar Civil Aviation Authority directives. Your flight was 4 or 5 hours later and hence no I do not expect a G/S agent who has probably been on shift since 6am to be aware or up to date about this or let alone even know what FAA is. I think your anger should be directed elsewhere.
You were aware that the 787s were grounded so I don't know why you were stressed. Had you not known then the blame lies with you not being updated.
On the contrary. I did know about the fleet being grounded. What gave rise to my stress and agitation was the QR groundstaff not only knowing about this, but also denying there was a problem with the aircraft. They were the ones that challenged me when I asked (to confirm) that the metal had been switched - denying and saying there was no problem. A simple "let me check sir" would have sufficed and prevented the entire episode. Again, I chuckle on here at the QR defenders making excuses and blaming me for QR's dreadful approach to customer service.
I suppose it's also my fault that they never respond to requests for feedback / refunds and/or other customer comments?