HP 41 not working

[Frido Bohn]

(12-18-2017 07:38 AM)jebem Wrote:  There was a very good reason why HP finally changed that design on the later half nut models after all.

This statement made me curious.
What did HP change in the design to make the half nuts less prone to malfunction, especially with regards to the broken post problem? (I'd like to introduce a new abbreviation for the HP41 enthusiast: 'BPP' aka broken post problem )