I have killed it a number of times today and over months. There is no indication that it is working correctly no loot glow no interaction.
I have hit if not killed Rukhmar several times without loot interaction or gold gain. I have ranged 46k damage to 509k damage on it. I have been first last and several in between hits and yet nothing.
Please inform us why loot table is broken for this NPC and provide the appropriate gold and loot drops that were not functioning.
Is that the world boss in WoD? You can only kill him once a week to get loot from him.
Also, his loot will just drop to you, as you do not loot his corpse.
EDITED TO ADD: In addition, his mount is not obtainable via bonus roll.
World bosses are one loot opportunity per week per character. Their loot appears directly in your bag if there is any (usually there isn’t). Not all bosses allow bonus rolls (Rukhmar is one of those).
AFAIK, nothing you have described seems out of the ordinary.