Organfreak, FWIW, I have recalled tentative conclusions drawn by others in my post no. 1646 on the “thread 6” in tech log. Briefly, some ATPL’s thought PF confused the status with overspeed.
I was reminded of other accidents, and also by somebody posting earlier, that stressed people can fix on a presumed problem and keep trying to correct it, even when their efforts are unsuccessful – it is a “how the brain works” thing.