It had a stacked "Too many duchies held" modifier, however the Exarchs having maxed out demesne prevented sub-factions from triggering (and even if - that'd be my vassals' problem, not mine).
And yes, it's ERE-specific pretty much (At least I have never went as far as to set up ducal viceroyalties elsewhere, if only for them being buggy).
I am not sure if this somehow increased in frequency after Holy Fury- given I played a full Roman Reformation this patch, and having done S.P.Q.R when Legacy of Rome first came out, it might simply be I've spent more hours observing it recently than the years prior.
On a related sidenote, "AI being allowed to hand out viceroyalties even as vassal" is in the patchnotes, so hopefully it will work out normally without having to dump everything on one guy to prevent infighting.
And yes, it's ERE-specific pretty much (At least I have never went as far as to set up ducal viceroyalties elsewhere, if only for them being buggy).
I am not sure if this somehow increased in frequency after Holy Fury- given I played a full Roman Reformation this patch, and having done S.P.Q.R when Legacy of Rome first came out, it might simply be I've spent more hours observing it recently than the years prior.
On a related sidenote, "AI being allowed to hand out viceroyalties even as vassal" is in the patchnotes, so hopefully it will work out normally without having to dump everything on one guy to prevent infighting.