Arena master bugged?

[Dreamwell]

Hi, when i try to loot the gurubashi arena chest, i am able to loot all the items except for the arena master trinket. See my screenshot attached. 

When i open the chest, it is empty, there is no arena master trinket in there.

I have already obtained 12x arena master trinkets before and handed them in to get the arena grand master. The arena master item should not be limited to players who have not obtained the arena grand master. It is blizzlike to obtain 2x arena grand master trinkets.