I also got the impression that the idol "wanted" to be stolen by Arabella, maybe it also wasn't too fond of the Rite of Thorns - though I don't know if artefacts can be this sentient.
Given how gods tend to act in a more quiet way,and the entire situation happening in the background,it's incredibly likely Papa Sil had a hand in it and tried to use it as a "maybe they'll get it" moment before Khaga happened.
