The whole point of a swing keel is to reduce the vessels draught in harbour or at anchor, but provide stability when sailing. It wouldn't be normal to have the keel down at anchor - it would be liable to significant damage if it hit the bottom. and even put the vessel at risk.

I did mention emergency procedures. Basically it's 1,2,3 .. if anchored etc.

.. the robustness of modern materials and engineering that that at the extreme, as unfortunately happened here ..

Speculations galore whilst expecting bias-free outcome. Yes, it needs investigating etc.