The broken DPA 6061 arrived, I suspect the electronics is fine and the capsule is broken. It's non-CORE, and the U(I) curve and teardown confirmed what I suspected: it's the topology from the Audio-Technica patent. The outer device is a PNP transistor, the JFET is behind the backplate of the capsule. There are some other surprises, I will send a follow-up later this week.
