When I reached 85 settlements, I had the surprise of seeing the majority of my empire suddenly turn blue, even as I was preparing to raise legions against the seleucids. Now, this took me completely by surprise, and after reading what it was about on this forum, I decided to disable it for this playthrough. I did want to keep the traits that came with the successful quelling of the rebellion though, so I edited the background script of Roma Surrectum 3.1 accordingly. Here it is, in case anyone is interested :
https://mega.nz/#!Ng8i3aja!Ydf3Alruc...htSvL9FRoZfB08

To install : you need a save before the rebellion started (ie, you have no cities revolting or captured by rebels yet). Replace the following file with the one I linked above : Play_Rome\data\scripts\show_me\background_script.txt
Load your save, continue playing.

It seems to work fine in my game. The settlements don't rebel, and the faction leader is named dictator for life. I had one stack of rebels spawn, but eh, whatever. I don't care enough to dig further into the code. Most importantly, I can send my 10 legions to take Syria and go up to Persepolis and Babylon .