The forensic report on the failure of the cable sockets is at https://www.thorntontomasetti.com/sites/default/files/2022-0.... Unlike the linked article this includes detailed diagrams and discussion explaining how these sockets worked and how they failed.

My attempt at a quick summary: the Arecibo instruments were held up by heavy steel cables, which are composed of a bundle of 126 to 216 individual wire strands twisted together, where each wire strand is about 1/4 inch diameter. At the cable ends these were anchored in sockets. The socket is conical, widening out towards where the wire ends go. The wire strands of the cable would be separated in a "broom" shape to fill out that conical area, and then the whole thing filled in with molten zinc.

The failure mode of these zinc-filled sockets is for an inner core cylinder, about the same diameter as the cable body, to pull out from the socket while outer strands of the cable which are broomed out of that core either snap or pull free from the zinc plug.

This failure mode hadn't really been seen prior to the Arecibo collapse, partly because it is a long term process where the zinc slowly flows under stress over decades.

Thanks for the quick summary