sealed chest bug

Good afternoon, 3 weeks ago I completed the mission "the last battle of the Exanime King" when I completed it I gave the mission.
I have been killing the Exanime King for the last few weeks to get my chest, but when I killed him I went to strip him and there were only the weapons and the marks, there was no trace of the chest so I was left without my tabard and my mount :c
I don't know, maybe it was bugged or something.
I would like please if you could help me with my problem.
thanks in advance