The weekly raid quest was Flame Leviathan Must Die. I had the quest before entering the instance.
I have screenshots to prove that I was there when it was killed, as I got to roll on the loot that dropped; however, my weekly raid quest did not complete.
I understand Warmane is a free, private server, and there are going to be issues sometimes, so usually I don't complain or open tickets; however, the loss of 10 total badges every week is a big hindrance to progression.
you can abandon the quest and try Sartharion must die, you still have 1 week to complete any Raid quest ( you are not forced to do the one from NPC, anyone can share you a different Raid quest)