Birth and Death feature is disabled in the save file you have uploaded. The death preference was always disabled by default but enabling death by default has broken the old and new saves alike. Can you start a new fresh campaign with death is disabled to check if someone is dying or not? This needs to be fixed and working correctly on new, fresh campaigns.
The same ****...nobles and companions started to die in battles with patch 1.5.5. like ordinary soldiers!
Of course, I understand that realism and all that ... but if we have realism - and companions die like ordinary soldiers - then the training of companions and their equipment must be done the same as for ordinary soldiers.
In order to equip a companion in the armor of the level of a high-ranking unit, you need to spend a lot of time to find this armor and so much money that more than 1000 human units in this armor could be hired with this money!
And suggesting that we start a new campaign with each patch is not very correct, given that the passage of one campaign can take hundreds of hours of real time.
What is the fun of playing if you constantly have to start over and can never finish?