I'd move AI not getting desertions to high priority, same as random general spawns.
The AI is very poor at protecting it's generals and moving it's crusades in a way that avoids desertions.

If you removed these advantages the AI gets then the AI would be very easy to beat as you could just wipe the family line out easily and the AI's Crusades would never reach their targets.

It's 100% clear to me thats it's a well thought out feature that helps the AI work and not a bug in any way shape or form.