This isn't a new thing, but I've noticed a couple of very egregious examples since 1.8 (probably due to the number of rebellions) - rebels are far far more interested in sieging provinces than defeating armies, even if said armies are trying to recapture provinces that the rebels had occupied.
In my recent game as Zazzau, Soghai had annexed Mossi, and of course, patriots for the latter had appeared. Songhai tried to beat them and in the process lost pretty much their entire army and manpower, leaving them with 3 or 4 units lead by, interestingly enough, a general with 3 siege. The rebels, down to one rather large stack, went around seiging the ex-Mossi provinces one by one, closely followed by the handful of Songhai troops which promptly recaptured the each province before the rebels could take the next one, meaning the rebels never controlled more than one province at a time. This went on for about a decade before I decided enough was enough and invaded Songhai and killed both sides. All the rebels needed to do to achive independance was to turn round and kill the Songhai troops before they got on with occupying their provinces, but nope, sieging is far more important.
Now, certainly, I'm not suggesting that the moment rebels spawn, they all converge on your armies and kill them, that wouldn't be fair or fun. But I think there does need to be somewhat of a change in their priorities. Particularly for those rebels that are trying to occupy specific provinces (e.g. nationalists), if there are troops in those provinces, especially if they're trying to recapture provinces captured by the rebels, they should try to attack those troops should they feel they have a decent chance of victory, rather than focusing solely on sieging and only fighting if they happen to blunder into an army on the way to siege somewhere else.
In my recent game as Zazzau, Soghai had annexed Mossi, and of course, patriots for the latter had appeared. Songhai tried to beat them and in the process lost pretty much their entire army and manpower, leaving them with 3 or 4 units lead by, interestingly enough, a general with 3 siege. The rebels, down to one rather large stack, went around seiging the ex-Mossi provinces one by one, closely followed by the handful of Songhai troops which promptly recaptured the each province before the rebels could take the next one, meaning the rebels never controlled more than one province at a time. This went on for about a decade before I decided enough was enough and invaded Songhai and killed both sides. All the rebels needed to do to achive independance was to turn round and kill the Songhai troops before they got on with occupying their provinces, but nope, sieging is far more important.
Now, certainly, I'm not suggesting that the moment rebels spawn, they all converge on your armies and kill them, that wouldn't be fair or fun. But I think there does need to be somewhat of a change in their priorities. Particularly for those rebels that are trying to occupy specific provinces (e.g. nationalists), if there are troops in those provinces, especially if they're trying to recapture provinces captured by the rebels, they should try to attack those troops should they feel they have a decent chance of victory, rather than focusing solely on sieging and only fighting if they happen to blunder into an army on the way to siege somewhere else.