Look carefully Carana. He didn't even alert above the cupboard where Ccat lay. He alereed above the cupboard, which was to the left of Ccats cupboard.
Yes, Sadie, I'm aware of that, and that was my first reaction as well. However, the issue seems to be the scent cone (where odour concentrates), which may not be where the object actually is.
That said, it doesn't explain why he didn't alert to CC when he first played with it.
You are more interested in the papers on top; I'm more interested in the fact that Kate had been carrying CC around with her for months and that it would therefore have had irrelevant decomp scent in it (Kate's - and despite having been washed).
In an occupied (and, therefore aired, villa), the scent may not have presented the "bouquet" that Eddie was used to being tasked to find. However, unless it can be formally excluded, he may have been zooming in on a partial "bouquet" of nothing other than the inevitable decomp in this porous toy due to Kate carrying it around with her for months. Placing it in an enclosed area (as opposed to the aired living area), could easily have concentrated the compounds that he would have reacted to and which would have risen via the partially open cupboard doors and concentrated wherever a breeze was coming from.