GM's unf don't know shit about what happens in WoW. These things were somewhere between 0.01 - 0.1% drop rate and in total there was maybe 50-60 of them listed on NA/EU. IMHO this is no different than the Legion Legendaries which can in fact drop from ANY NPC which was proved in 1 single case since Legion went Live almost a year ago. Hell, there are people out there that still don't have the Onyixia Mount, God Mount from TBC, Ravenlord, Timelost, etc. All of those also share in common what these 810 relics do, a stupidly low drop rate.
Without a Blue confirming an actual removal of them from the loot table, no volume of GM answers will ever put it to rest.