Some battery makers like Duracell have begun putting a bitter coating on CR2032 batteries to prevent children from eating them.
As The Loop points out, Apple's AirTag battery replacement support document that was published earlier this month specifically warns against bitterants and says that these coatings might cause the battery not to work.CR2032 batteries with bitterant coatings might not work with AirTag or other battery-powered products, depending on the alignment of the coating in relation to the battery contacts.The alignment of the coating in relation to the battery contacts is at issue, so to ensure the battery will work, AirTag users should buy replacement CR2032 batteries that do not have any kind of coating.