Trove of Smoldering Treasures just dropped Cloak of Steeled Nerves for me, but that wasn't in ATT's list. ATT has me at 4/5 items for that chest, even though there are quite a few more that I could still get from it.

It could be due to the fact that I am on a Demon Hunter, which wasn't released at the time?

Strange... I wouldn't think Class has anything to do with the logic going on for this particular container. But it's possible.

According to the data I see, the particular cloak you mentioned along with basically every possible 'Common Boss Drop' for WoD dungeons should show in the list for the Trove, so it should be far higher than 5 Things to collect from it...

Alright, this is fixed now. The original issue was due to a sneaky bug in how the population for this container was being calculated in-game, and then it got bugged again when I adjusted that logic to resolve some situations within WoD dungeons themselves.