I was playing with Albinus in the Severus scenarios and something weird happened.
I had taken control of Italy and was soundly beating the Severan incursions into my territory, the Severans were also beaten by the Parthian and Armenian backed Pescenius on the other side of the map, the only front where I was having some problems was Hispania where a isolated Severan landng force took a couple of towns in my soft underbelly.
And then suddenly way before the enddate I got a defeat screen saying Pescenius won because of a rovolt in Rome which put the city in hands of unaligned rebels, which I found weird since nothing indicated that loosing Rome meant instant defeat. Is this a normal rule I failed to notice or something else might have happened?