Wouldnt call it a bug if your the only person who has experinced this. We did this last night no problem no bugs event went was done and the person moved onto the next part. I also asked in trade and everyone else said that there was no issue eithers. Might have just been something you guys did wrong im not sure but its clearly not a bug, might have a been a bug or glitch.
Did you try running out and resetting the raid to redo the event?