Here's hoping this is the last of many posts spread throughout the Forum regarding development of RAW files in APB (because they will have been fixed in RC 1 ;) ). However, FWIW it seems that the Digital Assistant is at the bottom of many of the issues.
Some posts have been to the effect that the Develop persona in .25787 has benefitted greatly from the DA. Other folks have almost given up after getting blown out whites or funereal blacks. I was mainly in the former group, but have recently had a bunch of unusable developed files (mostly in the "funereal" category).
However, re-reprocessing with DA off, and doing minimal manipulations in the DP before going to Photo Persona for the main editing, gave results that were in a different league all together.
So, looking forward to RC 1, and if there is no change, will post this as a bug.
With thanks to MikeFromMesa for helpful discussions that led to this conclusion.