Let us take a look at what silicon is so heavily guarded by the charging case:
Our X-ray imagery shows some quality issues in this chip's solder joints. Empty spaces, known as voiding, could be evidence of low quality standards, or a rushed product release. Could issues with the AirPod case be what delayed release?
NXP 1610A3 charging IC (as seen in iPhones 6s and SE and both iPad Pro models)
Texas Instruments BQ24232 power management IC