What pets are these boxes still dropping then?
Maybe the game is trying to tell you something, have you ever run an unlocked 'Pet and Taming' skill gain pet and seen the impact on your looter gains whilst hunting?
Just run the right click, My avatar, Progress tool to see what I mean.
Pets are not just for xmas...smiles.
Rick
ps: I am running a level 56 Royal Chirin, so I notice such benefits, I don't know if level matters though (hopefully it matters).
edit: I guess you don't even have to unlock one to test it, you could I assume buy a stable buff assuming your pet qualifies to add the buff from a stable. Skinning is dynamic.