Some owners of broken AirPods received one replacement earphone with firmware that has not yet officially been released.
And the problem is not even that, but that the AirPods requires the same installed firmware to work together. Since the new 2D3 has not yet been released, it is impossible to update the second earphone to it. Bottom line: only one accessory works.
This mainly concerns AirPods 2, but there are also dissatisfied owners of AirPods Pro. There are a lot of similar grievances on Reddit , and technical support cannot help.