No 12v systems work

According to the simarine panel , the house batteries have not gone below  55%.

Is the latching relay programmable?

I would call it "remote battery disconnection" because it can only disconnect the circuit by remote. Reconnection can only be made manual.

If you are running batteries at low SOC, they get more or less damaged. Especially AGM batteries. Hanse is trying to avoid a less SOC, by disconnecting the service circuit, but still running safety devices like bilge pumps by permanent circuit.

The signal for disconnecting the service circuit comes from MPC: https://www.mastervolt.com/products/masterbus-interfaces/multipurpose-contact-output/

This MPC gets the SOC from the MasterVolt Shunt.

You can change the SOC limit for the MPC signal by configuration the MPC (or Shunt, I forgot) by https://www.mastervolt.com/products/masterbus-interfaces/masterbus-usb-interface/

I don't know why your battery was disconnected, even with SOC of >55%.

Maybe there is another/wrong configuration, or your display is showing another SOC than your Masterbus-Network.

I think you can disable the remote disconnection by cutting the orange cable from Blue Sea remote switch to MPC.