[Endoperez]

Did she have a fire shield?

This seems to be a bug, pretenders unable to move (sphinx and friends) die if unable to retreat, but the code seems to forgot to check this for pretenders highly fatiqued.

I think the rout of your army happens because the game checks which side routs (after the limit of 30 rounds of battle has filled) without taking already retreating army into account. Then your side retreats (though it would take bad luck for this to happen twice).